Sponges
a) have larvae which are motile and move via the motion of cilia
b) are the simplest diploblastic animals
c) have a nerve net but not a central nervous system
d) have feeding cells called dinoflagellates

Have larvae which are motile and move via the motion of cilia. (Ans. A)

Explanation:

Sponges: They are belongs to porifera phylum and defined as the simplest species. In sponge for particular function they are containing specialized cells, and they lack true tissues. All sponges are marine or aquatic in nature.

Sponge lives in contact with water because it helps them to excretion, gas exchange, and feeding. They can filter out the food, eliminate waste, and absorb dissolved oxygen with the help of body structure of sponge is dedicated to moving water.

Sponges produce motile larvae through the process of sexual reproduction, and move with the motion of cilia or budding formation through the process of asexual reproduction.

poor water quality affects most estuarine organisms, including commercially important fish and shellfish. the pollutants that have the greatest impact on the health of estuaries include toxic substances like chemicals and heavy metals, nutrient pollution (or eutrophication), and pathogens such as bacteria or viruses.

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.