An orange roughy fish is a fourth-level consumer that requires almost ten times the amount of food available from the primary producers in the ecosystem. why isn't more energy available from the primary producers?

a. primary producers are not very efficient and lose most of their energy to the environment.
b. there is too much competition from other fourth-level consumers, leaving very little available to the orange roughy.
c. only a fraction of energy is passed through each level, so there is less available to upper-level consumers.
d. the energy flow is unbalanced and tends to move toward the lower levels.

Read this summary of a scientific theory: "cells are the most basic structural and functional units of life. all living organisms are made up of one or more cells. all cells that are alive in the world today came from pre-existing cells." which of the following would require this theory to be modified? -a.) a survey finds that a majority of people believe viruses carry out the basic processes of life. -b.) a prominent scientist says she feels strongly that one day the theory will be challenged by life on other planets. -c.) the dna of unicellular and multi-cellular organisms is shown to have many fundamental similarities. -d.) scientific observations show that microscopic organisms living in the deep ocean are not made up of cells.