A gene mutation impacts a single gene, while a chromosomal mutation impacts part of a chromosome, which contains many genes. The answer is a chromosomal mutation.
Things around us are usually made up of combinations of elements. These combinations are called molecules. Molecules make up combinations called compounds.
Water is an example. There are 2 oxygen atoms and 1 hydrogen atom (oxygen and hydrogen are elements). Together there molecules make up H2O (water) which is a compound.
I hope this makes sense! I'm happy to answer any other questions you might have :)
