Which of the following is not a hormone that regulates stages of digestion?

auxin

cholecystokinin

gastrin

secretin

Auxin is not a hormone that regulates the stages of digestion. Auxin can only be found in plants. They are hormones in plants that cause the elongation of cells in shoots. They are also responsible for regulating the growth of plants. These hormones are also responsible for the growth and control of fruit and flower development in plants. Auxin hormones inhibit the growth of lateral buds that’s why plants grow upwards more than outwards.

In present time, these hormones are artificially produced in laboratories because they are used in the agriculture industry to speed up plant growth and regulate how fast the fruits will ripen.

"do a testcross with a homozygous recessive plant."

as in mitosis, dna replication occurs during interphase.   in meiosis, it occurs specifically in s phase of interphase 1.