1. which of the following statements regarding the moon is correct?

a. the moon is tidally locked to earth.
b. the moon's surface exhibits plate tectonic activity.
c. the moon's surface exhibits active volcanism.
d. the moon's surface doesn't have any craters.

2. how are elements that are heavier than hydrogen spread throughout the universe?

a. when a star collapses into a neutron star
b. when a star explodes as a supernova
c. when a star forms into a red giant
d. when a star collapses as a black hole

3. the milky way is held together by a black hole's gravitational force. since the stars near this black hole move at a high speed, what can you infer about the black hole?

a. its location
b. its size
c. its depth
d. its speed

4. suppose scientists believe that they've discovered a new planet. which of the following must be true for the object they've found to qualify as a planet?

a. it must be capable of supporting life.
b. it must have minimal gravity forces.
c. it must be shaped like an ellipsis.
d. it must follow a closed orbit around a star.

: )

1

The moon's surface exhibits active volcanic activity.

Explanation:

According to observations made from outside earth's surface, the moon has got active volcanic activity going on there.

Other than the moon, the other ones are:

This volcanic activity causes mass movement of land masses from their original position to a new position.

2

B. When a star explodes as a supernova

Explanation:

Elements are spread thought the universe in many different ways.

Elements that are heavier than hydrogen are formed in the massive stars and spread in the universe when the massive stars end in supernova explosions.

After this explosions, this elements that there before are held in the massive stars are released into the universe.

3

B. Its size

Explanation:

By accessing the speed at which the objects around the black hole move, we can determine its mass which is its size.

Since a black hole cannot be seen, we identify its mass and location through observing and analyzing the movement of objects like stars around it, if they appear to be moving at a very high speed, then that infers that there is a large black hole that is making the stars spin.

4

D. It must follow a closed orbit around a star.

Explanation:

In order for an object to qualify to be a planet it must follow a closed orbit around a star.

A good example is the planet earth, it follows a closed orbit around a star with the star being the sun.

Other qualifications are:

It must have enough gravitational pull that leads it to be in a spheroidal shape.

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.