The small multicellular spheres by which some plants reproduce a sexually is called A. protonemas

B. archegonia

C. gemmae

D. rhizoids

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.

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.