A. colorful, marine worm whose body is flattened dorso-ventrally. swims
through the water using a wavelike motion.
phylum?

Phylum platyhelminthe

Explanation:

Although a few of the free living marine and terrestrial species are very beautiful, most species are not particularly attractive to the human mind. Their body is dorso-ventrally flattened. They exhibit bilateral symmetry.   They do not have a body cavity and are acoelomate.  The movement of most platyhelminthes is using a wavelike motion that is controlled by longitudinal, circular, and oblique layers of muscle as they contract and relax simultaneously.

answer: all : )

explanation:

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

i hope this : )