Microbes in Human Welfare — BIOLOGY STD 12 Science — Question

Flowering plants have developed many devices to discourage self-pollination and to encourage cross pollination. Explain three such devices.

Explain logistic growth with equation.

The following graph shows the species-area relationship. Answer the following question as directed.

1. Name the naturalist who studied the kind of relationship shown in the graph. Write the observation made by him.
2. Write the situations as discovered by the ecologists when the value of 'Z' (slope of the line) lies.

1. 0.1 and 0.2
2. 0.6 and 1.2

What does 'Z' stand for?

3. When would the slope of the line 'b' become steeper?

The enzyme DNA polymerase in E.coli is a DNA dependent polymerase and also has the ability to proof-read the DNA strand being synthesised. Explain. Discuss the dual polymerase.

Different animals respond to changes in their surrounding in different ways. Taking one example each, explain 'some animals undergo aestivation while others hibernation. How do fungi respond to adverse climatic conditions?

How do you distinguish between humification and mineralisation?

Name the important mammary gland secretion that provides resistance to a newborn.

Why is that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher.

The use of biocontrol measures will greatly reduce our dependence on toxic chemicals and pesticides.###Give an importance of virus include in genus neucleopolyhedro virus.###How microbes are useful as Biocontrol agents? Explain.

A forest hardly has any carnivores. Census of herbivorous mammals was taken and plotted as a graph shown below:

Identify the curve that will explain the population growth of herbivores. Give reasons for your answer.