Which of the following is not a practical application of gravity? A. It keeps Earth in orbit around the sun
B. The moon has no gravity because it has no atmosphere.
Ο O O O O
C. It keeps the moon in orbit around Earth.
D. It keeps the galaxies from flying apart.

(The answer is B.)
(Putting this up to help y’all pass)

answer; a muscle cell, another neuron and a of the above

satellites are frequently used to make observations of the orbit on earth

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.