What type of rock forms when preexisting rocks undergo changes in response to a modification of their environment, without first melting? igneous rocks sedimentary rocks metamorphic rocks meteorites?

The answer is Metamorphic rocks. Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form". The original rock (protolith) is subjected to heat and pressure causing profound physical or chemical change. The protolith may be a sedimentary, an igneous, or even an existing type of metamorphic rock.