Human Reproduction — BIOLOGY STD 12 Science — Question

Alien species invasion is one of the causes of biodiversity loss. Explain with the help of an example.

OR

Sometimes alien species affect the indigenous organisms leading to their extinction. Substantiate this statement with the help of any two examples.

Most living organisms cannot survive at temperature above 45ºC. How are some microbes able to live in habitats with temperatures exceeding 100ºC?

Read the following statements carefully and give a term for each of them.

1. Programmes at a national level to attain total reproductive health as a goal are called.
2. A rapid increase in population over a relatively short period is called.
3. A rapid decline in death rate is called.
4. Permanent movement of people out of an area is called.

Suggest the aspects of reproductive health which need to be given special attention in the present scenario.

Mention the location and function of tapetum inthe microsporangium of angiosperms. State the characteristic features of the cells forming this layer.

Why do we experience shivering during winters when the temperature is very low?

How is GIFT different from IUI?

In a dihybrid cross white eyed, yellow bodied female Drosophila crossed with red eyed, brown bodied male Drosophila produced in F₂ generation, 1.3 per cent recombinants and 98.7 per cent progeny with parental type combinations. This observation of Morgan deviated from Mendelian F₂ phenotypic dihybrid ratio. Explain, giving reasons, Morgan’s observations.

Name the interaction in the following:
Mycorrhizae living on the roots of higher plants.