Professor Marcus is studying gene expression in the liver cells of a mouse. She observes that when a steroid hormone enters the liver cells, the cells begin producing a wide variety of new proteins.

In a classic experiment using pea shape, mendel conducted two separate genetic crosses. in the first cross the parent plants were “true breeding” for pea shape; one had round peas ( r )and the other had wrinkled (r). the first cross produced a filial 1 generation of all round peas. in the second cross, mendel bred plants from the filial 1 generation. this cross produced different results. out of approximately 1000 plants, about 75% were round and 25% were wrinkled.

Penelope studies how the structure and function of the nervous system is related to behavior. she is a psychologist

What type of appendages do sponges cnidarians roundworms annelids mollusks arthropods echinoderms and vertebrate have? jointed, not jointed, absent