What determines an organism's characteristics?

How many trophic levels are there in the following food chain? phytoplankton - shrimp - perch - pike - osprey

Plsss > .< compare and contrast the characteristics of flatworms rounds worms and earthworms

The blue particles in this image are able to cross the cell membrane through simple diffusion. how will they be transported? outside the cell inside the cell o a. the substances will move directly across the membrane from outside the cell to inside the cell. b. the substances will move through channels in the membrane proteins from outside the cell to inside the cell. o c. the substances will move through channels in the membrane proteins from inside the cell to outside the cell. o d. the substances will move directly across the membrane from inside the cell to outside the cell.