A carbon atom has 6 protons and 6 electrons. Carbon has three naturally occurring isotopes, carbon- 12, carbon-13, and carbon-14. Which of these statements is true about carbon and its isotopes?

Which of the following is the main purpose of a human community?

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.

Match the correct terms to their descriptions a system in which only energy but not matter is exchanged frozen water in snow part of geosphere that includes only soil a thin layer between the troposphere and the stratosphere cryosphere tropopause closed system pedosphere