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

When two or more embryos develop from a single fertilized egg, the condition is known as Polyembryony. In the case of humans, it results in forming two identical twins.This phenomenon is found commonly in plants and animals. The nine-banded armadillo usually gives birth to four identical young ones, owing to polyembryony.

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Practical material is not here why????

Posted by Dewank Singh 7 years, 2 months ago

CBSE > Class 12 > Biology

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Honolulu techniques

Posted by Sarthak Yadav 7 years, 2 months ago

CBSE > Class 12 > Biology

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Lac operon

Posted by Ashraf Sheikh 7 years, 2 months ago

CBSE > Class 12 > Biology

1 answers

Purusottam Singh 7 years, 2 months ago

SWTCH OFF(negative regulation) 1.The regulator(i) produces repressor mRNA which forms repressor protein 2.The repressor protein binds with the operator so RNA polymerase cannot bind on promoter and transcription does not occur SWITCH ON(positive regulation) 1.In presence of inducer such as lactose the repressor get inactivated by inducer 2.Now inactivated repressor cannot bind with the operator 3.This allows RNA polymerase to access the promoter and transcription proceeds 4.After transcription lac mRNA is produced which on translation gives ß galactosidase,permease ,transacetylase

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The energy released during cell respiration is immediately used to synthesise a molecule called

Posted by Sukhbir Paul 7 years, 2 months ago

CBSE > Class 12 > Biology

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Rna interference

Posted by Komal Meena 7 years, 2 months ago

CBSE > Class 12 > Biology

1 answers

Yogita Ingle 7 years, 2 months ago

This method involves silencing of a specific mRNA of the parasite due to complementary dsRNA molecule that binds to and prevents translation of the mRNA. The source of this complementary RNA could be from an infection from viruses having RNA genomes or mobile genetic elements that replicate via RNA intermediate.

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What are steroides

Posted by Dhananjay Kumar 7 years, 2 months ago

CBSE > Class 12 > Biology

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why does the lac operan some time after the addition of lactose the medium where e-coli was growing why?

Posted by Aman Mishra 7 years, 2 months ago

CBSE > Class 12 > Biology

1 answers

Harisha Goothy 7 years, 2 months ago

Sample paper question??

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What is ramsar site in india

Posted by Bhupendra Patel 7 years, 2 months ago

CBSE > Class 12 > Biology

2 answers

Jayant Tehlan 7 years, 2 months ago

Not in NCERT but in syllabus Chapter 15

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Harisha Goothy 7 years, 2 months ago

As such its not there in ncert...even ilooked it up and couldn't find it...

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Most important topic in all chapter

Posted by Anurag Pandey 7 years, 2 months ago

CBSE > Class 12 > Biology

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Harisha Goothy 7 years, 2 months ago

See the previous year question papers and the syllabus weightage..

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A child has blood group o.if the father has blood group A and mother blood group B,work out the genotypes of the parents and the possible .genotypes of the other ofsprings.

Posted by Shivani Kumawat 7 years, 2 months ago

CBSE > Class 12 > Biology

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Papa . 7 years, 2 months ago

AO for father BO for mother

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How vertebrates show divergent evolution

Posted by Jyoti Kataria 7 years, 2 months ago

CBSE > Class 12 > Biology

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How I get pass in biology? Because I am weak in biology

Posted by Kalas Sahu 7 years, 2 months ago

CBSE > Class 12 > Biology

2 answers

Harisha Goothy 7 years, 2 months ago

Just do together with scanner and read ncert .ull get 90+

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Navya Singh 7 years, 2 months ago

Do ncert ques nd read ncert thoroughly. ..that is enough

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Give the scientific name of source organism from which the first antibiotic was produced

Posted by Siya Lathi 7 years, 2 months ago

CBSE > Class 12 > Biology

3 answers

Priyanka Singh 7 years, 2 months ago

Penicillium notaum

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Kalas Sahu 7 years, 2 months ago

Penicillin Notatum

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Abc Kamboz 7 years, 2 months ago

Penicillin notatum

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How I get good marks in biology? Because I am weak in biology please tell me anyone

Posted by Kalas Sahu 7 years, 2 months ago

CBSE > Class 12 > Biology

1 answers

Mohit Sepat 7 years, 2 months ago

Read ncert question and ncert throughly

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What is cortical reaction?

Posted by Danista Rawal 7 years, 2 months ago

CBSE > Class 12 > Biology

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Which is known as the Development of more than one embryo with in an ovule ?

Posted by Rashmirani Jena 7 years, 2 months ago

CBSE > Class 12 > Biology

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Yogita Ingle 7 years, 2 months ago

Polyembryony is the presence of more than one embryo in a seed. In many Citrus and mango varieties, some of the nucellar cells surrounding the embryo sac start dividing, protrude into the embryo sac and develop into embryos.

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How I will get good marks in biology? Because I am weak in biology

Posted by Kalas Sahu 7 years, 2 months ago

CBSE > Class 12 > Biology

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Please tell me how to read biology?

Posted by Kalas Sahu 7 years, 2 months ago

CBSE > Class 12 > Biology

1 answers

Vishali Raina 7 years, 2 months ago

Read from ncert

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Name the oldest fossils

Posted by Mithun Prasad 7 years, 2 months ago

CBSE > Class 12 > Biology

1 answers

Àñshul Shärmã 7 years, 2 months ago

Stromatolites....

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Difference between seed and ovule ?

Posted by Jitendra Jaiswal 7 years, 2 months ago

CBSE > Class 12 > Biology

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How do evolved eundosperm? Explain

Posted by Jitendra Jaiswal 7 years, 2 months ago

CBSE > Class 12 > Biology

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What is pcr

Posted by Madhuvan Singh 7 years, 2 months ago

CBSE > Class 12 > Biology

2 answers

Shivani Kumawat 7 years, 2 months ago

Polymer chain reaction used in amplifying at 5'end

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Madhuvan Singh 7 years, 2 months ago

Pcr is polymerase chain reaction help in amplifying at 5'end

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Sielent features of carbon cycle

Posted by Aman Dehraj 7 years, 2 months ago

CBSE > Class 12 > Biology

1 answers

Mohit Sepat 7 years, 2 months ago

Cycling pool is air and water ......reservoir pool is atmos0here ,hydrosphere lithosphere.....it is under gasesous cycle of matter ...rainfall bring lot of dissolved carbon

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Write any five features of Indian forest?

Posted by Jitendra Jaiswal 7 years, 2 months ago

CBSE > Class 12 > Biology