A tralt that occurs in 400 individuals out of a total of 1,600 individuals occurs with a probability of

tissue

explanation:

it is actually formed by geoup of cells which is tissue

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

instead of copying and pasting things off of tests or work done on computer which im sure you did, try and read over the question carefully