Xeric environment is found in deserts where temperature remains high in the day and low during the night and air humidity is very low.

Correct Option: B

Xeric environment is found in deserts where temperature remains high in the day and low during the night and air humidity is very low.

This is one of the reasons for organisms being homeostatic (constant body temperature).

Correct Option: B

This is one of the reasons for organisms being homeostatic (constant body temperature).

Two or more species which are reproductively isolated from each other but are morphologically quite similar are known as sibling species. Sympatric species are developed due to reproductive isolation and occur in overlapping or same area of geographical distribution. Parapatric species are developed in adjacent geographical areas meeting in very narrow regions of overlap.

Correct Option: C

Two or more species which are reproductively isolated from each other but are morphologically quite similar are known as sibling species. Sympatric species are developed due to reproductive isolation and occur in overlapping or same area of geographical distribution. Parapatric species are developed in adjacent geographical areas meeting in very narrow regions of overlap.

The keystone species in an ecosystem are those who are the main contributors to the ecosystem.

Correct Option: D

The keystone species in an ecosystem are those who are the main contributors to the ecosystem.

Soil particles size defines its texture. The mineral particles present in soil, vary enormously in size, the fine fragments (consisting of sand, silt and clay particles) and coarse fragments (gravel, copples and stones). The relative proportion's of sand, silt and clay in a soil is referred as soil texture. Fine textured soil have more of clay particles. Water holding capacity-Larger soil particles like sand, gravel have large pores. These have less water holding capacity and higher percolotion rate. Field capacity is the amount of soil moisture or water content held in soil after excess water has drained away.

Correct Option: A

Soil particles size defines its texture. The mineral particles present in soil, vary enormously in size, the fine fragments (consisting of sand, silt and clay particles) and coarse fragments (gravel, copples and stones). The relative proportion's of sand, silt and clay in a soil is referred as soil texture. Fine textured soil have more of clay particles. Water holding capacity-Larger soil particles like sand, gravel have large pores. These have less water holding capacity and higher percolotion rate. Field capacity is the amount of soil moisture or water content held in soil after excess water has drained away.