Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions for Biology

Non viral and non vector methods are sometimes used to transfer genes or alien DNA into a plant cell. Explain one such method used in genetic engineering.

"Forests provide intangible benefits to us." Explain by taking three different areas, how.

The IUCN Red Data List (2004) in the last 500 years documents the extinction of nearly 784 species including ______.

Assertion (A): Decomposition process is slower if detritus is rich in lignin and cutin.

Reason (R): Decomposition is largely an oxygen requiring process.

By using Punnett square depict the genotypes and phenotypes of test crosses (where green pod colour (G) is dominant over yellow pod colour (g)) in Garden pea with unknown genotype.

Which one of the following groups faces maximum threat of extinction? 

The sixth extinction in progress currently is different from all previous extinctions on earth as it is ______.

Observe the contents 1, 2, 3 and 4 of soil samples A, B and C shown in the graph. If the temperature and soil moisture of all soil samples are identical, which soil sample (s) will show faster decomposition?

1 indicates lignin content, 2 indicates chitin, 3 indicates nitrogen content, and 4 indicates sugar content

Explain the process of hormonal regulation of spermatogenesis.

Can we call human evolution as adaptive radiation?

Name a genus of baculovirus.

Why are scared groves highly protected?

How do organic farmers control pests?

Name and explain the type of interaction that exists in mycorrhizae and between cattle egret and cattle.

What is mutualism?

List any four techniques where the principle of ex-situ conservation of biodiversity has been employed.

State the medicinal value and the bioactive molecules produced by Streptococcus, Monascus and Trichoderma.

Apart from being a part of the food chain, predators play other important roles. Mention any two such roles supported by examples.

Name two commonly used bioreactors.

Name the bioactive molecules produced by Trichoderma polysporum and Monascus purpureus.