Sexual Reproduction in Flowering Plants — BIOLOGY STD 12 Science — Question

How is rabies caused? Write its symptoms and control measures.

Write any three contraceptive methods.

Somatic chromosome number is 40. What shall be the chromosome number in the cells of seminiferous tubules?

Not all hydrophytes are pollinated by water. Justify by giving two examples.

Distinguish between
Litter and detritus.

Draw a diagram of transverse section of an angiospermic anther. Label any six parts.

How do mammals living in colder regions and seals living in polar regions able to reduce the loss of their body heat?

Your advice is sought to improve the nitrogen content of the soil to be used for cultivation of a non-leguminous terrestrial crop:

1. Recommend two microbes that can enrich the soil with nitrogen.
2. Why do leguminous crops not require such enrichment of the soil?

(a) Tobacco plants are damaged severely when infected with Meloidogyne incognitia. Name and explain the strategy that is adopted to stop this infestation.
(b) Name the vector used for introducing the nematode specific gene in tobacoo plant.###How has RNA it technique helped to prevent the infestation of roots in tobacco plants by a nematode Meloidogyne incognitia?

List any three enzymes involved in the process along with their functions.