Compare and contrast the reasons cell division is important for unicellular and multicellular organisms. 2. provide an example of why cell division remains important to an adult organism even after it is fully developed. 3. what is the role of growth factors? 4. cells divide, differentiate, or die. what is differentiation?

desert perennials often survive by remaining dormant during dry periods of the year, then springing to life when water becomes available. most annual desert plants germinate only after heavy seasonal rain, then complete their reproductive cycle very quickly.

the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.