Answer:
B. It is done by humans to select certain traits useful to us.
Explanation:
There are two main types of selection: natural and artificial. Natural selection is all of the other answers, it is seen over generations and allows the fittest to survive. It also occurs with no human intervention. However, artificial selection is done by humans. It occurs when humans breed animals to best fit their needs. This is best seen in dog breeding.
I believe it is the 'black swallower'
hope i could help :)
