After several cycles of cell division, a fertilized cell develops into a hollow ball of cells called a(n) (2 points) a) amnion b) blastocyst c) fetus. d) follicle.

Blastocyst

Explanation: After fertilization the cell remains as it is with no cell division for the next 12 hours( single cell). Then after next 30 hours the single cell divides from 1 into 2 and then it divides into 4 after the next 15 hours.

At the end of 3 days the fertilized egg develops into a berry like structure which is known as morula made of of 16 cells.

Then these cell continues to divide further into blasocyst which is hollow pinhead structure. It consist of hundreds of cells.

option c is the correct answer.

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.