At about age most boys reach spermarche, which is the first spontaneous ejaculation of sperm-laden fluid.

Viruses are different from bacteria in that they can remain dormant on non-living surfaces they can be found just about anywhere they can infect just about every form of life

For a comparative or experimental investigation, scientists often make a testable about a scientific question, and then they test it in the investigation. a. control b. hypothesis c. procedure d. system

What is true of all organisms in the kingdoms protista, plantae, fungi, and animalia? a. they are multi-celled. b. they are photosynthetic. c. they have cells that contain membrane-bound organelles. d. they contain cells that lack membrane-bound organelles.