Draw a labelled diagrammatic sectional view of a human seminiferous tubule.

(a) List the three states the annuals and biennial angiosperms have to pass through during their life cycle.
(b) List and describe any two vegetative propagules in flowering plants.

During a medical investigation, an infant was found to possess an extra chromosome 21. Decribe the symptoms the child is likely to develop later in the life.

Explain the role(s) of the following in biotechnology.
(a) Restriction endonuclease
(b) Gel-electrophoresis
(c) Selectable markers in pBR322

Describe how do ‘flocs’ and ‘activated sludge’ help in sewage treatment.

p²+2pq+q² Explain this algebraic equation on the basis of Hardy-Weinberg’s principle.

Write the steps you would suggest to be undertaken to obtain a foreign-gene-product.

(a) What precaution(s) would you recommend to a patient requiring repeated blood transfusion?
(b) If the advise is not followed by the patient there is an apprehension that the patient might contract a disease that would destroy the immune system of his/her body. Explain with the help of schematic diagram only how the immune system would get affected and destroyed.

A number of passengers were severely burnt beyond recognition during a train accident. Name and describe a modern technique that can help hand over the dead to their relatives.

(a) What is inbreeding depression?
(b) Explain the importance of ‘selection’ during inbreeding in cattle.