Which structures are part of the body's first line of defense against pathogens? a. white blood cells b. red blood cells c. lymph nodes d. mucous membranes me !

Which is true of chemicals? a. things containing chemicals always cost a lot of money. b. chemicals are never dangerous. c. chemicals are in many substances in a home. d. chemicals are rarely found on earth.

Which of these is an intensive property of a substance

What is the number of neutrons in an atom with atomic mass of 35