Scientists group materials together it is easier to compare and study them that way

The provided question is incomplete, the correct and complete question is as follows:

Choose the answer that best completes the sentence below.

Scientists group materials together it is easier to compare and study them that way.

A however

B but

C although

D because

The correct answer is - option D because.

Explanation:

Researcher and scientists tries to group material together on their similarities and difference to one another which makes it easier to study and compare various type of materials.

It is the one of major reasons to differentiate materials between groups like liquids state, gases state,  plasma state and solid state materials. One can easily see the difference and comparison is very clear on this type of grouping of materials.

Thus, the correct answer is - option D.