A major cause of genetic variation within a species is the result of...​

Radiation or a different species creating an offspring with a different species

Explanation:

a axis of a graph is a color or shade so we can all go outside and have a party so we can eat   some grilled cheese sammiches and broccoli and have some ugly fun times

i don't know why i put this, i know its not the i was just bored : p

delete this answer while you can