Which statement is true for single-celled organisms? a. they are often harmless. b. they always cause disease. c. they only live inside humans. d. they reproduce in a complicated process.

I believe the answer is d. Single celled organisms like bacteria have a complicated way of reproducing. In most cases the single celled organisms produce asexually by dividing themselves into two equal halves.

In some developing nations the percentage of the animal protein from fish in the diet can be as high as 25 percent.  about 85% of fish caught is used for human consumption.  the remainder is converted into fishmeal and fish oil.