Sexual Reproduction in Flowering Plants — BIOLOGY STD 12 Science — Question

What is obsessive-compulsive disorder? How is it different from borderline personality disorder? What are the two most common obsessions that affect adolescents?

What do you mean by reproductive health? Mention the different ways in which people are made aware of the significance of reproductively healthy society.

What is high altitude sickness? Write its symptoms.

What is red list? Give two uses of red list.

Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20 mg/L, 8 mg/L and 400 mg/L respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?

Is pollination and fertilisation necessary in apomixis? Give reasons.

A person is born with a hereditary disease with a weakened immune system due to deficiency of an enzyme. Suggest a technique for complete cure for this disease, identify the deficient enzyme and explain the technique used for cure.

Why do all the fresh water organisms have contractile vacuoles whereas majority of marine organisms lack them?

Which layer of uterus undergoes cyclic changes during the menstrual cycle?