During cell division, the chromosomes are held together at the? A. spindle fibers
B. cell membrane
C. centromere
D. nucleolus

C

Explanation: The two chromatids of a duplicated chromosome are held together at a region of DNA called the centromere. Centromeres are the attachment points for microtubules, which are responsible for the guiding the movement of chromosomes during mitosis and meiosis.

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.

b) the inside picture would look at a very high temperature in a very low ph