Question

today’s new vocabulary:
biodiversity - the number of different animals or plants in an
environment
gene - the part of the cell that is responsible for transmission of
inherited traits
metamorphosis - change of parts, physical form, or character
the changing of an organism that makes it
better able to fit in its environment
masking
adaptation
adjustment
coloring

Explanation:

The definition "The changing of an organism that makes it better able to fit in its environment" matches the term "adaptation". "Masking" is about hiding, "adjustment" is a general change, and "coloring" relates to color, none fit as well as "adaptation".

Answer:

B. adaptation