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

Because it causes the death of all the other organisms present inside or on the water bodies by utilising all the oxygen of water and making defeciency of oxygen and light inside the water. It was introduced in bengal because of its beautiful flowers but soon it became harmful for aquatic organisms. As fish is the supplement food in bengal so it caused the scarcity of food and hence known as terror of bengal.

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Sandeep Kumar Dwibei 5 years, 6 months ago

Because they drain out all the oxygen from water that causes death of fishes in bengal

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Best reference books for biology physics and chemistry

Posted by Devil ? 5 years, 6 months ago

CBSE > Class 12 > Biology

6 answers

Shivani Pradhan 5 years, 6 months ago

physical chemistry GRB the best

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Siddharth Tiwari 5 years, 6 months ago

Arihant

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Gurdev Saggu 5 years, 6 months ago

Dinesh for physics

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Rishika Sahu 5 years, 6 months ago

Only ncert

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Sandeep Kumar Dwibei 5 years, 6 months ago

Biology by master your biology and chemistry by modern abc

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Arnab Haldar 5 years, 6 months ago

Physics By S.L. Arora

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Explain the types of fertilization with example why one type is advantageous over the other

Posted by Puja Puja 5 years, 6 months ago

CBSE > Class 12 > Biology

2 answers

Insha Khalid 5 years, 6 months ago

There are 2 types of fertillization: 1.Ezterna F:fusion of male and female gamatte occur outside the body of female.ex.frog etc 2.Internal F:fusion of male and female gamatte inside female body .ex. human etc Advantage over one another is that chance of fertillization is less in external but in internal it is about 75%

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Ayaan Ali ?? 5 years, 6 months ago

External and internal & internal is advantage..bcx as it takes place inside d mother's body and it also hve less hrm frm d predators

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Sea anemone and hermite crab possess which type of relationship?plss explain with reason.

Posted by Priyal Bansal 5 years, 6 months ago

CBSE > Class 12 > Biology

1 answers

Rishika Sahu 5 years, 6 months ago

Protocorporation

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How many primary producer required to feed tertiary consumers in grassland ecosystem

Posted by Ritu Negi 5 years, 6 months ago

CBSE > Class 12 > Biology

1 answers

Khuskaran Sidhu 5 years, 6 months ago

12 million for 6 3° consumers

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Class 11 BIOLOGY has more significance for NEET exam or class 12 BIOLOGY...?

Posted by Alisha Bhanwara 5 years, 6 months ago

CBSE > Class 12 > Biology

1 answers

Ritss ?? 5 years, 6 months ago

11th

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How many year elephant live

Posted by Deepak Dhouchak 5 years, 6 months ago

CBSE > Class 12 > Biology

3 answers

Rahul Aryan 5 years, 6 months ago

African forest elephant: 60 – 70 years

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Rahul Aryan 5 years, 6 months ago

Asian elephant: 48 years

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Rahul Aryan 5 years, 6 months ago

African bush elephant: 60 – 70 years

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Kya hum humanities stream me biology ka additional subject le sakte hai???

Posted by Sujal Tomar 5 years, 6 months ago

CBSE > Class 12 > Biology

1 answers

Ekansh Singhal 5 years, 6 months ago

Yes

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Name the scientists and write how did they explain mendals law after the chromosome were discovered

Posted by Leepakshi Kumari 5 years, 6 months ago

CBSE > Class 12 > Biology

1 answers

? ? 5 years, 6 months ago

Sutton and boveri in 1902.....and explain chromosomal theory of inheritance....

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Which one is not the product of transgenic experiments A. High nutritional value in grains B. Drought resistant crops

Posted by Bhumi Khandelwal 5 years, 6 months ago

CBSE > Class 12 > Biology

1 answers

Insha Khalid 5 years, 6 months ago

Drought resistant crops

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Expressions of only one of the parental character in F1 and expressions of both in F2 can be explained by A) law of dominance B)law of segregation C) punnet square Pls give reason for your answer

Posted by Sonal Sharma 5 years, 6 months ago

CBSE > Class 12 > Biology

1 answers

Nishant Kapoor213 5 years, 6 months ago

A) Let parent are both homozygous, male(TT) and female (tt), In F1 Tt alleles having progeny born And this progeny have phenotype of tall. Law of dominance proved. B) if we self pollinate this progeny then, In F2 progeny TT, Tt, tt as u can see tt phenotype is dwarf. It shows that recessive allele hide it itself and pass to successive generations and express itself it only in homozygous condition. Thus, law of segregation proved. Note:- mendelian laws are not always correct. Still,we appreciate them as they are the pillars of genetics.

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What is amino acid?

Posted by Insha Khalid 5 years, 6 months ago

CBSE > Class 12 > Biology

2 answers

Rishika Sahu 5 years, 6 months ago

Structural unit of protein

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Surjeet Yadav 5 years, 6 months ago

It is constuent of aminegroup and carboxyllic acid

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What is nucleic acid

Posted by Insha Khalid 5 years, 6 months ago

CBSE > Class 12 > Biology

1 answers

Sonal Sharma 5 years, 6 months ago

Nucleic acids are long chain of amino acids Nucleic acid are DNA

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What are alleles? Please explain it easy.

Posted by Ayush Kumar 5 years, 6 months ago

CBSE > Class 12 > Biology

4 answers

Rahul Raj 5 years, 6 months ago

Alleles are the alternative forms of a gene.

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Nishant Kapoor213 5 years, 6 months ago

Consider this analogy u have a pair of shoes similiarly there is a pair of allele for specific trait generally. Say one shoe called spake it not any word i think so for sake of understanding, similiarly one single allele called gene or an allele of .... trait. A shoe or spake is same and two spake make one pair of shoe that we say shoes. Now pair of allele/gene called alleles. Gene is nothing just a coding sequence like u live in a street ur street name is gali no. 6 next street is known as gali no. 7 so names are given just to differentiate both even both are made of cement,etc. In thus way u relate gene is just coding sequence and we name that coding if its useful or we know whats its function like this AGCTTAA code for eye color now this part of DNA called gene because it do something that we know.

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Insha Khalid 5 years, 6 months ago

It is a series of genes which express traits

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Yogita Ingle 5 years, 6 months ago

It is a member of a pair or series of genes that occupy a specific position on a specific chromosome.
They occur in pairs.
Pair of alleles make opposing phenotypes.
Alleles occur in pairs and then they are differentiated into homozygous and heterozygous
Example- Blue eyes, green eyes

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The first cellular form of life evolved......

Posted by Nancy Bagoria 5 years, 6 months ago

CBSE > Class 12 > Biology

4 answers

Nishant Kapoor213 5 years, 6 months ago

In water hypothesis in abiogenesis theory.

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Surjeet Yadav 5 years, 6 months ago

On bare surface

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Ayan Tiwari 5 years, 6 months ago

In water environment

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Sindhu Philip 5 years, 6 months ago

RNA

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How was biology paper set 2

Posted by Nancy Bagoria 5 years, 6 months ago

CBSE > Class 12 > Biology

4 answers

Mahesh M 5 years, 6 months ago

Sappa

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Surjeet Yadav 5 years, 6 months ago

Easy

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Ayan Tiwari 5 years, 6 months ago

Moderate

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Subham Sahu 5 years, 6 months ago

Not so difficult.

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How was all paper my paper was fantastic

Posted by Dheeraj Jandu 5 years, 6 months ago

CBSE > Class 12 > Biology

3 answers

Nandlal Rajwade 5 years, 6 months ago

My also

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Ayan Tiwari 5 years, 6 months ago

All were good except physics

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Nancy Bagoria 5 years, 6 months ago

My also

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What is amoebic dysintry

Posted by Jitu Choudhary 5 years, 6 months ago

CBSE > Class 12 > Biology

1 answers

Sonal Sharma 5 years, 6 months ago

Amoebiasis or amoebic dysentery Is caused due to a protozoa named Entamoeba histoliytica . Its vector for. Spreading is mosquito. It causes cramps ,pain in stomach, bleeding with excess mucous along with bloody stools.

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Does corpusluteum was formed when the secondary oocyte was not fertilize

Posted by Abhishek Maurya 5 years, 6 months ago

CBSE > Class 12 > Biology

3 answers

Nishant Kapoor213 5 years, 6 months ago

No corpus lutem form when 2° oocyte rupture the tertiary follicle. It's formation has no role with fertilisation. Indeed it ruptures if fertilisation will not take place within 2-3 days of ovulation.

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Surjeet Yadav 5 years, 6 months ago

Secret large amount of progesterone hormones

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Ayush Kumar 5 years, 6 months ago

Yes. They degenerate after some processes.

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Menstruation cycle

Posted by Pradeep Bohora 5 years, 6 months ago

CBSE > Class 12 > Biology

2 answers

Nishant Kapoor213 5 years, 6 months ago

Menstrual cycle only happen in primates, Phases in menstrual cycle are ●Menstrual phase ●follicular phase ●ovulation ●luteal phase Its repeat periodically generally from puberty called menarche to old age(40-45) called menopause stopping of menstrual cycle.

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Insha Khalid 5 years, 6 months ago

It is a type of reproductive cycle which occur in female. It occur after attaing puberty. It occur after interval of every 28 days

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What is the reason of unwanted weeds

Posted by Mohan Singh 5 years, 6 months ago

CBSE > Class 12 > Biology

2 answers

Nishant Kapoor213 5 years, 6 months ago

Unwanted weeds concept isn't defined independently. If any desired plant growth is affected due to other plant which have grown on its own called weed.

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Insha Khalid 5 years, 6 months ago

Because unwanted weeds take the nutrients from soil more rapidly than plants. That's why they grow rapidly

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Is there any neet aspirant?

Posted by Prince Jaat 5 years, 6 months ago

CBSE > Class 12 > Biology

5 answers

Naren Pal 5 years, 6 months ago

Yeah

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Rahul Raj 5 years, 6 months ago

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Sonal Sharma 5 years, 6 months ago

Yesss

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Heena Pathak 5 years, 6 months ago

Yhh

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Mahesh M 5 years, 6 months ago

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Write a short note on pollination

Posted by Sanskruti Hirani 5 years, 6 months ago

CBSE > Class 12 > Biology

2 answers

Priya Bungla 5 years, 6 months ago

It is the act of transferring pollen grains from Male anther of a flower to female stigma

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Riya Rana 5 years, 6 months ago

Pollination is the transfer of pollen grains from the anther to the the stigma of the pistil. It can be of three types autogamy, geitonogamy (same plant in both) and xenogamy (different plant's pollen).

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What is boidiversity

Posted by Ningombam Nandaraj Singh 5 years, 6 months ago

CBSE > Class 12 > Biology