Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

Biological Oxygen Demand or BOD increases with increase in water pollution. In this reference, answer the questions that follow:

1. At a particular segment of the river near a sugar factory, the BOD is much higher than the normal level. What is it indicative of?
2. What will happen to the dissolved oxygen and living organisms in this part of the river?

What are adhesive and cohesive forces?

Explain about the factors that affect water absorption.

Distinguish between Ectotherms and Endotherms.

How is puberty attained in females? Will a female normally remain reproductively capable even after age 50? If not then what makes her incapable?

There are many animals that have become extinct in the wild but continue to be maintained in zoological parks.
Which type of biodiversity conservation is observed in this case?

Define genomis. Give any two applications of it.

Explain the process of development of a mature human female gamete from the time it is initiated till the formation of ootid.
OR
Describe in sequence the formation of an ovum from an oogonium in a human female.

Sketch and label the T. S. of the thyroid gland.

Explain the cause of chromosomal disorders in humans. Describe the effect of such disorders with the help of an example each involving.

1. autosomes, and
2. sex chromosomes.