Describe the process of gaseous exchange between : -
i) alveoli of lungs and blood in respect of partial pressure of respiratory gases.
ii) the body tissue and blood

prophase: we can observe the chromosomes to coil up and condense. they become visible. nuclear membrane and envelope disintigrate.s

metaphase: chromosomes align at the center, the metaphase plate. spindle fibers attach to centromeres of the sister chromatids. they meet at kinetochores.

anaphase: sister chromatids are pulled towards each opposing centromere, set on different poles.

telophase: chromosomes are now clustered up only on either sides of the cell. nuclear membranes reform, and a new cell wall forms along the cell plate. this will lead to cytokinesis, the process that divides the cell membrane and forms the cell wall.

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.

regents of the university of california v. bakke, 438 u.s. 265 (1978), was a landmark decision by the supreme court of the united states. it upheld affirmative action, allowing race to be one of several factors in college admission policy.