The head of a human offspring turns down and prepares to enter the birth canal during
a. the first trimester
b. the second trimester
c. the third trimester
d. birth

The child turns its head towards the birth canal during:
C. the third trimester
Other changes that occur during the third trimester of pregnancy are that the baby starts to practice breathing, develops a complete nervous system and skeletal system, starts detecting light and many other things.

There is sand and mud

Lipid because of the high percentage of carbon to carbon bonds, which store more energy than other bonds.