Compare and contrast an active solar heating system with a radiator system.

A system that uses the sun's energy without requiring mechanical devices (pumps or fans) to distribute the collected heat are called solar system while radiator system uses fuel to heat the water. in active solar heating system, the SUN's energy used to heat water.

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 : )

thats not even an aswer choice