Answer:
Allotropes
Explanation:
Because it is the same element the chemical conposition is the same i.e. The atoms that make the substances are identical. Allotropes can be crystalline or amorphous and sometimes they can be varied in properties.
The answer is b, anything that has mass and takes up space
Answer:
c. 
Explanation:
= Initial distance between asteroid and rock = 7514 km = 7514000 m
= Final distance between asteroid and rock = 2823 km = 2823000 m
= Initial speed of rock = 136 ms⁻¹
= Final speed of rock = 392 ms⁻¹
= mass of the rock
= mass of the asteroid
Using conservation of energy
Initial Kinetic energy of rock + Initial gravitational potential energy = Final Kinetic energy of rock + Final gravitational potential energy
