CBSE > Class 12 > Biology | CBSE Board | Homework Help

Ask questions which are clear, concise and easy to understand.

Ask Question

Differentiate between prokaryotes and eukaryotes

Posted by Divya Priya 6 years, 9 months ago

2 answers

Nasima Khan 6 years, 9 months ago

In the prokarotes there is no membrane and do not contain a well developed nucleus but in other hand eukaryotes contain a fully mature membrane and nucleus.

0Thank You

Kumkum Saini 6 years, 9 months ago

The main difference between prokaryotes and eukaryotes is this: eukaryotic cells contain membrane-bound organelles, such as the nucleus, while prokaryotic cells do not. Differences in cellular structure of prokaryotes and eukaryotes include the presence of mitochondria and chloroplasts, the cell wall, and the structure of chromosomal in eukaryotes, and the absence of those organelles in prokaryotes. DNA.

0Thank You

ANSWER

Differentiate between inbreeding and outbreeding List any three advantages and one important disadvantages of inbreeding practice in animal husbandry

Posted by Vaishnavi Kumari 6 years, 9 months ago

CBSE > Class 12 > Biology

1 answers

Yogita Ingle 6 years, 9 months ago

Inbreeding : Inbreeding refers to the mating between closely related individuals within the same breed for 4-6 generations.
Outbreeding: It refers to the breeding of unrelated animals either of the same breed but do not have common ancestor or of different breeds.
Advantage :

It brings the homozygosity in the population.
Increases the productivity of the inbreed population.
Eliminates or reduces less desirable genes.

Disadvantage : It exposes the harmful recessive alleles.

1Thank You

ANSWER

a. application of each one of the following Amniocentesis A. B. Lactational amenorrhea C. ZIFT b. Prepare a poster for the school programme depicting the objectives of : "Reproductive and Child Health Care Programme".

Posted by Saksham Aggarwal 6 years, 9 months ago

CBSE > Class 12 > Biology

1 answers

Shikha Manger 6 years, 9 months ago

Prokaryotic cell

0Thank You

ANSWER

Results of regular consumption of sustainable resources

Posted by Anas Anwar 6 years, 9 months ago

CBSE > Class 12 > Biology

0 answers

ANSWER

What is vegetative pro pagation.

Posted by Mitali Jain 6 years, 9 months ago

CBSE > Class 12 > Biology

2 answers

Sia ? 6 years, 9 months ago

Vegetative propagation is a type of asexual reproduction in which a new plant is developed from the vegetative parts such as stem, leaf and root. It can be done by both natural and artificial methods.

0Thank You

Kritika Choudary 6 years, 9 months ago

Type of asexual reproduction in which from vegetative propagules new plant form

0Thank You

ANSWER

Nhi yaar nhi pdhi academy me jati thi paise dekr pass ho gayi 11th me sirf friendship ki or kuch nhi kiya but now i want to do something that's why i need help .

Posted by Kritika Choudary 6 years, 9 months ago

CBSE > Class 12 > Biology

0 answers

ANSWER

Unicellular organisms are immortal whereas multicellular organisms are not.Justify.

Posted by Subham Sahu 6 years, 9 months ago

CBSE > Class 12 > Biology

1 answers

Kumkum Saini 6 years, 9 months ago

. Single celled organisms reproduce by cell division into two individuals, there is no natural death for them and hence they are considered immortal. ➡️. In multicellular organisms, reproduction occurs in specialised organs involving specialised cells, their body as a whole dies due to ageing and senescence.

1Thank You

ANSWER

Acha SL or HCV short form h thanku for telling me because mne isi saal se pdhna suru kiya h plz aap mujhe support krna. Kroge na

Posted by Kritika Choudary 6 years, 9 months ago

CBSE > Class 12 > Biology

2 answers

Nasima Khan 6 years, 9 months ago

Yrr SL arora thik h HC verma samjh nhi aayegi aapko kyuki aapne 11 class nhi padhi or HC ki language bhi hard h

0Thank You

Ďãřşháñăã Yadav ? ? ? 6 years, 9 months ago

kyu apne 11th nhi padhi?

0Thank You

ANSWER

Alleles

Posted by Sahil Dhull 6 years, 9 months ago

CBSE > Class 12 > Biology

1 answers

Swati Kumari 6 years, 9 months ago

Two genes which occur on the same locus in homologous chromosome and the expression of a trait.

0Thank You

ANSWER

Ecg graph explain

Posted by Ambuj Singh 6 years, 9 months ago

CBSE > Class 12 > Biology

1 answers

Gurmeet Kaur 6 years, 8 months ago

A normal heart rhythm contains a P wave, a QRS, and a T wave. Knowing the normal amplitude, deflection, and duration of each component is essential to accurate rhythm and EKG interpretation.

1Thank You

ANSWER

Micropyle remains as a small pore in the seed coat of a seed

Posted by Pritha Biswas 6 years, 9 months ago

CBSE > Class 12 > Biology

1 answers

Prakhar Kumar 6 years, 9 months ago

Yes

0Thank You

ANSWER

What is the the different between genotype and phenotype

Posted by King Khan King Khan 6 years, 9 months ago

CBSE > Class 12 > Biology

2 answers

Prakhar Kumar 6 years, 9 months ago

Genotype depends on the gene these characters are not visible on the other hand phenotype characters are physical characters which are visible

0Thank You

Akhil Tiwari 6 years, 9 months ago

NCERT page no.72

0Thank You

ANSWER

Under which of the following conditions will therebe no change in the reading frame of following mRNA ? 5'AACAGCGGUGCUAUU3' (1) Insertion of G at 5th position (2) Deletion of G from 5th position (3) Insertion of A at G at 4th and 5th positions respectively (4) Deletion of GGU from 7th, 8th and 9th positions

Posted by Ďãřşháñăã Yadav ? ? ? 6 years, 9 months ago

CBSE > Class 12 > Biology

1 answers

꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 8 months ago

Option D is correct because in all other cases one or two are deleted which can lead to change in sequence of bases whereas in last case a complete codon(three) is removed so the there is no change in reading frame of mRNA

0Thank You

ANSWER

A gene locus has two alleles A, a. If the frequencyof dominant allele A is 0.4 then what will be thefrequency of homozygous dominant, heterozygousand homozygous recessive individuals in the population. (1) 0.36 (AA); 0.48(Aa); 0.16 (aa) (2) 0.16 (AA); 0.24 (Aa); 0.36 (aa) (3) 0.16 (AA); 0.48 (Aa); 0.36 (aa) (4) 0.16 (AA); 0.36 (Aa); 0.48 (aa)

Posted by Ďãřşháñăã Yadav ? ? ? 6 years, 9 months ago

CBSE > Class 12 > Biology

0 answers

ANSWER

A woman with blood group A marries a man with blood group O. Discuss the possibilities of the inheritance of the blood groups.

Posted by Yashvee .Student 6 years, 9 months ago

CBSE > Class 12 > Biology

2 answers

Tarun Kumar 6 years, 8 months ago

A o

0Thank You

Rachita Sharma 6 years, 9 months ago

i i HA HA.i. HA.i i. i.i. i.i From above cross, the possibilities are:- 50% chance of progeny with blood group A 50% chance of progeny with blood group O

0Thank You

ANSWER

Explain the two different ways of biodiversity conservation.

Posted by Aliya Joyson 6 years, 9 months ago

CBSE > Class 12 > Biology

1 answers

Sia ? 6 years, 9 months ago

There are two basic approaches for the conservation of biodiversity

Ex situ conservation (off-site conservation)
In situ conservation (on-site conservation)

In situ conservation, It is the conservation and protection of biodiversity in its natural habitat.

It helps in recovering population in the surroundings where they have developed their distinctive features.
Example National parks, biosphere reserves, wildlife sanctuaries.

Ex situ conservation It is the conservation of selected rare plants and animals in places outside their natural habitat

It helps in recovering population or preventing their extinction under conditions that closely resemble their natural habitats.
Example Botanical gardens, zoological parks, wildlife safari parks, gene banks, etc.

0Thank You

ANSWER

What is Spermatogenesis?

Posted by Yogesh Sharma 6 years, 9 months ago

CBSE > Class 12 > Biology

2 answers

Sia ? 6 years, 9 months ago

Spermatogenesis is the process in which spermatozoa are produced from spermatogonial stem cells by way of mitosis and meiosis. The initial cells in this pathway are called spermatogonia, which yield primary spermatocytes by mitosis.

Spermatogonia undergo first meiotic division to produce secondary spermatocytes. This further undergoes second meiotic division to form spermatids finally, spermatids are converted to sperms.

1Thank You

Tanya Mishra 6 years, 9 months ago

Formation of sperms is called as spermatogenesis

1Thank You

ANSWER

Who discovered double fertilization

Posted by Juli Rathor 6 years, 9 months ago

CBSE > Class 12 > Biology

1 answers

Yogita Ingle 6 years, 9 months ago

Double fertilization was discovered more than a century ago by Sergei Nawaschin and Grignard in Kiev, Russian Empire, and Léon Guignard in France. Each made the discovery independently of the other. Lilium martagon and Fritillaria tenella were used in the first observations of double fertilization, which were made using the classical light microscope.

1Thank You

ANSWER

Who discovered sertoli cells?

Posted by Abhay Gupta 6 years, 9 months ago

CBSE > Class 12 > Biology

2 answers

Rahul Dagar 6 years, 9 months ago

enrico sertoli

0Thank You

Sia ? 6 years, 9 months ago

Enrico Sertoli

2Thank You

ANSWER

Describe the formation and the function of corpus luteum

Posted by Abhay Gupta 6 years, 9 months ago

CBSE > Class 12 > Biology

2 answers

Abhay Gupta 6 years ago

What is estradiol

0Thank You

Sia ? 6 years, 9 months ago

Corpus luteum, yellow hormone-secreting body in the female reproductive system. It is formed in an ovary at the site of a follicle, or sac, that has matured and released its ovum, or egg, in the process known as ovulation.

Functions of corpus lectum:

It secretes a small amount of estradiol and much of progesterone. Through feedback, progesterone inhibits the secretion of FSH-RH from the hypothalamus to prevent the occurrence of next menstrual cycle,
It also secretes relaxin hormones.

2Thank You

ANSWER

What is the water Hyacinth

Posted by Mitali Jain 6 years, 9 months ago

CBSE > Class 12 > Biology

4 answers

Lily ☺ 6 years, 9 months ago

It is terror of bengal. Or scourge of water bodies. Absorbs O2 from water. Vegetative propagation Grows faster in stagnant water. Intoduced in india due to its beautiful flowers and shape of leaves.

4Thank You

Anshika Sharma 6 years, 9 months ago

It is a plant that absorb oxygen from water..

2Thank You

Mugha ? 6 years, 9 months ago

? It's scientific name is Eichhornia

1Thank You

Mugha ? 6 years, 9 months ago

? See ncert textbook.... Page no. 8.....1st paragraph

1Thank You

ANSWER

What term is given by you to the group of individuals which are genetically and morphologically identical

Posted by Shreya Agrahari 6 years, 9 months ago

CBSE > Class 12 > Biology

5 answers

Sia ? 6 years, 9 months ago

The term clone is referred to describe such morphologically and genetically similar individuals.

0Thank You

Abhay Gupta 6 years, 9 months ago

Clones are the organisms which are genitically and morphologicaly identical

0Thank You

S4S Education 6 years, 9 months ago

Clones

0Thank You

Mitali Jain 6 years, 9 months ago

Clone

0Thank You

Lily ☺ 6 years, 9 months ago

Clone

1Thank You

ANSWER

How is it that the embryo sac of some apomictic species look normal but contain diploid cells

Posted by Khalel Ahmed 6 years, 9 months ago

CBSE > Class 12 > Biology

1 answers

Meghna Thapar 5 years, 7 months ago

Replacement of the normal sexual reproduction 'by asexual reproduction without fertilization is called apomixis. e.g., replacement of the flower by bulbils and replacement of the seed by a plant. Apomitically produced offsprings are genetically identical to the parent plant. In flowering plants, apomixis is used in a restricted sense to mean angiosperm, i.e., asexual reproduction through seeds. In some plant species, it is common, e.g., Asteraceae, Poaceae. In some species, the diploid egg cell is formed without reduction division and develops into an embryo without fertilization. It is asexual reproduction in the absence of pollinators such as in extreme environments. In some species like citrus, some of the nucellar cells surrounding the embryo sac start dividing and develop into embryo. It occurs in the megaspore mother cell does not undergo meiosis, thus produces diploid embryo sac through mitotic divisions. Thus, it explains that, embryo sacs of some apomictic species appear normal, but producediploid cells.

0Thank You

ANSWER

How many type of reproduction

Posted by Saurabh Verma 6 years, 9 months ago

CBSE > Class 12 > Biology

5 answers

Mitali Jain 6 years, 9 months ago

Two types of reproduction Sexual and asexual

0Thank You

Kavita Gupta 6 years, 9 months ago

Sexual and. Asexual

0Thank You

Ďãřşháñăã Yadav ? ? ? 6 years, 9 months ago

there are two type of reproduction Asexual and Sexual.

1Thank You

Rishabh Soni 6 years, 9 months ago

3 types

1Thank You

Aksh Panchal 6 years, 9 months ago

1Thank You

ANSWER

1. you are given castor and Bean seeds which one of the two would you select to observe the endosperm? the development of endosperm precedes that of embryo in plants. justify 2. Differentiate between inbreeding and outbreeding. List any three advantage and one important disadvantage of inbreeding practice in animal husbandry

Posted by Vaishnavi Kumari 6 years, 9 months ago

CBSE > Class 12 > Biology

2 answers

Kumkum Saini 6 years, 9 months ago

Inbreeding refers to mating of related individuals. ... Outbreeding refers to matings between individuals from different populations, subspecies, or species. Outbreeding can result in a decline in reproductive fitness known as outbreeding depression, but this is less common than inbreeding depression.

1Thank You

Kumkum Saini 6 years, 9 months ago

1. Castor

1Thank You

ANSWER

Why are bald women rare ?

Posted by Ayush Kumar Singh 6 years, 9 months ago

CBSE > Class 12 > Biology

0 answers

ANSWER

What is test tube baby

Posted by Shankar Das 6 years, 9 months ago

CBSE > Class 12 > Biology

2 answers

Gursharn Kaur 6 years, 9 months ago

Test tube baby is the artificial method of producing basies artifically outside the female body. In this method ,sperms fuses with ovum in test tube not in the fallopian tubes of female reproductive system

1Thank You

Yogita Ingle 6 years, 9 months ago

Test tube babies are the babies produced through external fertilization fusion of a sperm with an egg cell is made to take place in a test tube in a suitable medium. Zygote so formed in planted in the uterus of female. The embryo & birth take place in the uterus and takes the normal birth.

1Thank You

ANSWER

Describe different stages of menstruation for 5 marks

Posted by Krishna Kumar 6 years, 9 months ago

CBSE > Class 12 > Biology

2 answers

Ďãřşháñăã Yadav ? ? ? 6 years, 9 months ago

➡️Follicular Phase: ✴️ This phase usually includes cycle days 6-13 or 14 in a 28 days cycle. ✴️ The follicle stimulating hormone (FSH) secreted by the anterior lobe of the pituitary gland stimulates the ovarian follicle to secrete oestrogens. ✴️ Oestrogen stimulates the proliferation of the endometrium of the uterine wall. ✴️ The endometrium becomes thicker by rapid cell multiplication and this is accompanied by an increase in uterine glands & blood vessels. ➡️Ovulatory Phase: ✴️Both LH & FSH attain a peak level in the middle of cycle (about 14 th day). ✴️ Oestrogen concentration in blood increases. ✴️ Rapid secretion of LH induces rupturing of graffian follicle and thereby the release of ovum. ✴️ In fact LH causes ovulation. ➡️ 4. Luteal Phase: ✴️ Includes cycle days 15 to 28. ✴️ Corpus luteum secretes progestrone. ✴️ Endometrium thickens. ✴️ Uterine glands become secretory

2Thank You

Gursharn Kaur 6 years, 9 months ago

Menstruation is the cylic changes which starts after the puberty . Menstrual cycle consists of 4 stages. These are as follows: Menstruation : During this stage their is removal of blood along with the uterus lining. This stage occurs upto 3-5 days Proliferative phase: This phase is also known as follicular phase. In this their is proliferation of uterine wall. Ovulatory phase : During this phase the secondary oocyte is released from mature graffian follicles. Luteal phase: this phase occurs during 15- 28 day cycle. In this phase the corpus lutem begins to develop.

2Thank You

ANSWER

Which is the best book for the preparation of basics of biology

Posted by Aryanika Agnihotri 6 years, 9 months ago

CBSE > Class 12 > Biology