Question

A substance will have a relatively rigid, unchanging shape when it is a

Answer 1

solid because it maintains their shape and is rigid 
in this case the answer would be letter "D" 

Answer 2

Answer:

Solid

Explanation:

Solid phase of matter is characterized by presence of less or no space between its particles. The atoms of the molecules are placed close to each other and are bonded together. Absence of gaps and tight bonding does not allow the particles of the substance to move part each other and results in rigidity and fixed shape.