Plant Growth and Mineral Nutrition — BIOLOGY STD 12 Science — Question

Greenhouse effect is boon or bane? Give your opinion.

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?

Nictitating membrane, Seymouria, Lung fish, Flipper of whale and wing of bird, Wing of insect and wing of bird, wisdom
tooth, Eye of octopus, an eye of mammal, vertebrate heart and brain.

Column I	Column II
(1) Homologous organs	————-
(2) Analogous organs	————-
(3) Vestigial organs	————-
(4) Connecting links	————-

Niche is a part of habitat'. Explain with the help of an example.

What is the meaning of sterilisation? Why is it essential in tissue culture?

What is outbreeding? Mention any two ways it can be carried out.

What is aminoacylation? State its significance.

Classify the following white blood corpuscles given below as per Column A and complete Column ‘B’. Select from the given options:
(i) Eosinophils
(ii) T-lymphocytes
(iii) Neutrophils
(iv) Basophils
(v) B-lymphocytes
(vi) Monocytes

Column A	Column B
(1) Phagocytic cells	————
(2) Cells involved in giving immune response	————
(3) Cells that increase during allergic and anti-allergic responses	————

The diagram shows the flow of energy through an ecosystem.

Which arrows represent the smallest amount of energy transferred between organisms and the largest amount of energy lost to the ecosystem?

Mention any one significance of fruit formation.