Which statement did Keller’s investigations of the movement of the planets explain? A. Jupiter has more moons than earth.

B. Gravity acts on all objects in the universe.

C. The sun is more massive than the earth.

D. Earth is not the center of the universe.

Put the following steps of the convection process in the correct order. 1. gravity pulls cooler matter downward. 2. the matter expands and decreases in density. 3. an up-and-down flow of matter produces a convection current. 4. matter is heated. 5. warmed matter is forced upward. question 2 options: a) 4, 2, 5, 1, 3 b) 2, 4, 3, 1, 5 c) 3, 2, 5, 4, 1 d) 1, 4, 2, 5, 3

Which gas found in the earth's atmosphere greatly impacts the daily range of temperature on earth. a) oxygen b) hydrogen c) nitrogen d) water vapor

Which of these substances does not protect against invaders in the nonspecific immune response? a. saliva b. mucus c. tears d. urine