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

Write the use of the following in biotechnology.
Microinjection.

(i) Write the complete name of IUDs.
(ii) IUDs secreting the hormone are said to be best contraceptive to keep space between children. Why?

During the secondary treatment of the primary effluent how does the significant decrease in BOD occur?

OR

During the secondary treatment of the primary effluent how does the significant decrease in BOD occur?

Explain the four basic process to increase or decrease in population density in a habitat.

Lianas are vascular plants rooted in the ground and maintain erectness of their stem by making use of other trees for support. They do not maintain direct relation with those trees. Discuss the type of association the lianas have with the trees.

'Intra-cytoplasmic sperm injection' and 'gamete intra fallopian transfer' are two assisted reproductive technologies. How is one different from the other?

What roles do enzymes play in detergents that we use for washing clothes? Are these enzymes produced from some unique microorganisms?

Distinguish between the roles of flocs and anaerobic sludge digesters in sewage treatments.

Three water samples namely river water, untreated sewage water and Secondary effluent discharged from Sewage treatment plant were subjected to BOD test. The samples were labelled in 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, 8mg/L and 400mg/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?

The diagram shows the flow of energy through an ecosystem.

Which arrows represent the smallest amount of energy transferred between organisms and the largest amount of energy lost to the ecosystem?