Human Reproduction — BIOLOGY STD 12 Science — Question

In what way anaerobic sludge diagestion is important in sewage treatments?

What are the various advantages of using genetically modified plants to increase the overall yield of the crop?

Elaborate how invasion by an alien species reduces the species diversity of an area.

A child suffering from thalassemia is born to a normal couple. But the mother is being blamed by the family for delivering a sick baby.

1. What is Thalassemia?
2. How would you counsel the family not to blame the mother for delivering a child suffering from this disease? Explain.
3. List the values your counselling can propagate in the families.

Answer the following questions:
Name the hormones secreted and write their functions:

1. By corpus luteum and placenta (any two) .
2. During Follicular phase and parturition.

Answer the following questions:
During a cross involving true breeding red flowered and true breeding white flowered snapdragon plants, the F₁ progeny did not show any of the parental traits, while they reappeared in F₂ progenies. Explain the mechanism using Punnett Square.

How does replication of the long DNA molecule occur? Explain the process.

OR

Explain the process of DNA replication with the help of a replicating fork.

Rohan and his friends emptied all the overhead tanks, which were not in use for last few months. Some people did not like this. Rohan and his friends explained and convinced them about the hygienic benefits of their act.

1. What was the objective behind their act?
2. Explain in brief the stages of life cycle of a malarial parasite in human body.
3. Which pathogen is responsible for malaria?
4. What values did Rahul and his friends promote?

(i) Define net primary productivity.
(ii) Explain with diagram that the pyramid of energy is always upright.

Describe the nature of inheritance of the ABO type of blood group in humans. In which ways does this inheritance differ from that of height of the plant in garden pea?