(1)As a cloud of gas and dust collapses on itself and becomes more dense, the temperature at the center of the cloud A, Increase

B, Decrease,

C, Stay the same.

(2)What is the first step in the nuclear fusion process?

A, two helium atoms combine to make one hydrogen atom

B, two hydrogen atoms combine to make one helium atom

C, two helium atoms combine to make one carbon atom

1. Option A.

Increase.

2. Option B.

two hydrogen atoms combine to make one helium atom

Explanation:

Stars formation occur In a cold or sense region called molecular clouds. It start when the fender part of the cloud collapse under gravity. The core tend to collapse first since they are denser than the outer cloud. As the collapse they form clumps and this intend form protostar and this process take 10 million years. As the center of the protostar is compressed, it heat up. The Temperature increases.

Nuclear fusion is a chemical reaction in which two lighter nuclei combines to form heavier nuclei. Two hydrogen atoms combine to form helium atoms

the backbone of the dna and rna compound is sugar phosphate.