Enhancement of Food Production — BIOLOGY STD 12 Science — Question

Although sexual reproduction is a long drawn, energy-intensive complex form of reproduction, many groups of organism in Kingdom Animalia and Plantae prefer this mode of reproduction.
Give at least three reasons for this.

Community service department of your school plans a visit to a slum area near the school with an objective to educate the slum dwellers with respect to health and hygiene.

1. Why is there a need to organise such visits?
2. Write the steps you will highlight as a member of this department, in your interactions with them to enable them to lead a healthy life.

Give three hypotheses for explaining why tropics show greatest levels of species richness.

Refer to the diagram given below and answer the questions that follows.

1. Label the parts A and B.
2. Which part of flower develops into seed and fruit?
3. What is the function of both the labeled parts?

1. Organic farmers prefer biological control of diseases and pests to the use of chemicals for the same purpose. Justify.
2. Give an example of a bacterium, a fungus and an insect that are used as biocontrol agents.

What is a test cross? How can it decipher the heterozygosity of a plant?

1. Mark the positive and negative terminals.
2. What is the charge carried by DNA molecule and how does it help in its separation?
3. How the separated DNA fragments are finally isolated?

Justify the statement ‘Vegetative reproduction is also a type of asexual reproduction'.

Answer the following questions:
What are mycorrhiza? How does it act as a biofertiliser?

What are plant growth regulators? Give the characteristics of plant growth regulators.