What does the term milankovitch cycles refer to?
a. alternating glacial and interglacial periods
b. advancing and retreating continental ice sheets
c. freezing and melting of fallen snow to shape glaciers
d. periodic changes in earth's orbit and axial tilt that affect climate

every el niño cycle is different. every year.

some scientists like gregory adcock agree with thorne's theory of regional continuity.

others, like chris stringer and ian tattersall, believe thorne's results may be contaminated or misinterpreted.

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.