List any two strategy adopted by bisexual flowers to prevent self-pollination .

Mention two strategies evolved to prevent self -pollination in flowers .

Assertion (A) : Emasculation is a process of removal of anther to prevent self pollination. Reason (R) : Anthesis is a period of opening of a flower.

Continuous self pollination results in inbreeding depression . Flowering plants have developed many devices to discourage self pollination and to enocourage cross pollination . Explain any four such mechanisms .

List any two wet-land in Tamilnadu.

Amazonian rain forests have the greatest biodiversity on earth. List any two hypotheses that are proposed by the biologists to account for the greater biological diversity.

List any two effects of noise pollution.

Flowering plants have developed certain outbredding devices to discourage self-pollination and encourage cross-pollination. One of these is not an examples of such outbreeding device.

Assertion : Self-incompatibility is a genetic mechanism which prevents self-pollination and thereby fertilisation by inhibiting either pollen germination or pollen tube growth in the pistil. Reason : In gametophytic self-incompatibility, the incompatibility reaction is determined by the genotype of the sporophytic tissue of the plant from which the pollen is derived.