How would the contractile vacuole of a freshwater amoeba respond if the organism was placed in seawater? a)with more contractions b)with fewer contractions c)the contractions would suddenly cease d)with the same frequency of contractions

The correct answer is Option (a) with more contractions. The primary function of contractile vacuole is to maintain the amount of water in the protoplasm of cell. For a freshwater amoeba there is a need of contractile vacuole because it pumps out the water and maintains osmoregulation. But when the amoeba is kept in sea water there is need of more contractions to expel the water and make the environment  inside amoeba same as that of sea water.

A) with more contraction

Explanation:

A contractile vacuole is the cavity which expel out excess water and waste from the cytoplasm of the amoebic cell. When the freshwater amoeba is placed in seawater, the excess saline water get expel out by contractile vacuole by undergoing more contractions.

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?