What’s going on?
These flies’ wings are shaped by genetics (DNA) and by their environment, in this case the temperature where they were raised.
The tiny-wing flies have a mutation that stunts the growth of the wings. But the final size of the wings also depends on the temperature in the lab where the flies lived. Cool temperatures lead to very tiny wings. Warmer temperature leads to pointy airplane wings.
The curly-wing flies also have a mutation; and the final outcome also depends on the temperature. At a higher temperature, the mutant wings are severely curled. At a lower temperature, they’re less curly.
In humans too, genes and the environment work together to shape our brains and bodies. You inherited genes from your parents that affect how tall you are, but nutrition and other factors also affected your height.