Microbes in Human Welfare — BIOLOGY STD 12 Science — Question

Name any two hormones found in the blood of a pregnant female only.

What is a vaccine? How do they act to provide long term immunity to an individual, who is vaccinated?
OR
Write the events that take place when a vaccine for any disease is introduced into the human body.

OR
How does a vaccine for a particular disease immunise the human body against that disease?

OR
Name and explain the type of immunity that is provided by injecting microbes deliberately during immunisation into the human body.

Name any one of the green house gases and its possible source of production on a large scale. What are the harmful effects of it?

What is the significance of Archaeopteryx in the study of organic evolution?

Differentiate between inbreeding and heterosis. What is inbreeding depression?

What is natural ecosystem? Explain with the help of suitable example.

Name the kind of cheese which possesses characteristic holes.

Certain bacteria are useful to mankind differently. Give examples.

The density of a population in a habitat per unit area is measured in different units. Write the unit of measurement against the following:

1. Bacteria.
2. Grass.
3. Banyan.
4. Deer.
5. Fish.