Which scientist was the first to propose that the earth spins on its axis and the
planets which are closest to the sun move faster around the sun than those that are
farther away?
a) kepler
b) ptolemy
c) aristotle
d) copernicus

Explanation:

D

letter D) Copernicus

Explanation:

He formulated an exquisite model of the universe that placed the Sun rather than Earth at the center of the universe. His publication called  De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), he created the heliocentrism school where he observe intrinsically that the Earth spins on its axis and the  planets which are closest to the Sun move faster around the Sun than those that are  farther away...

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation: