Reproductive Health — BIOLOGY STD 12 Science — Question

Explain with the help of an example, each of the three population interactions, where the organisms live closely together.

Explain what is meant by environmental resistance and its relationship to population growth.

'Predation is beneficial in long run'. Comment.

Explain the inheritance of haemophilia of normal man and hemophilic women.

Fertilisation is essential for production of seed, but in some angiosperms, seeds develop without fertilisation.

1. Give an example of an angiosperm that produces seeds without fertilisation Name the process.
2. Explain the two ways by which seeds develop without fertilisation.

Name the prominent South Indian and North Indian species of sugarcane used for cross-breending. List the desired qualities of the hybrid cane obtained from this cross.

How is corpus luteum formed and what is its important function?

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?

Differentiate the following and give examples:
Innate and acquired immunity.

(a) Write the conclusions drawn by Alexander von Humbolt based on his extensive exploration of South America.
(b) Study the graph given below :

According to Alexander von Humbolt, what do the symbols S, A, C, and Z used in graphs indicate in the context of a species and region relationship?