Astronomers have proposed the existence of an unexplained force that is causing the expansion of the universe to accelerate. what do they call this force? a) dark matter b) dark space c) dark stars d) dark energy e) dark holes

D Dark Energy

Explanation:

The expansion of the universe is explained on the basis of dark energy.

A force that is responsible for the expansion of the universe is named as the Dark energy. It is only a hypothetical form of energy. It seems to oppose gravity by exerting a negative and repulsive pressure.

Accelerated expansion of the universe is caused by the dark energy. Dark energy contributes to atleast 68% of the total energy that exists in the present day observable universe. These are details that are presented by the Standard model of Cosmology.

Dark matter neither emits nor absorbs light. It exerts immense gravity.

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form