The correct answer is B.
Krill is a type of small crustacean living in large schools, in the ocean. Krill have many anatomical adaptations in order to survive in the vast ecosystem of an ocean. One of these adaptations are the very fine filtering nets used by the krill to capture and acquire the necessary nutrients. Krill feed on some of the smallest living phytoplankton and the nets are used to filtrate the water and capture them. When the concentration of the phytoplankton is low, the nets are used to filter the water and feed on the captured algae.
