What is an exothermic chemical reaction?
a. it is a reaction that converts matter to heat.
b. it is a reaction that requires heat to proceed.
c. it is a reaction that draws heat from its surroundings.
d. it is a reaction that releases heat to its surroundings.

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.

How does the presence of oxygen affect the chemical pathways used to extract energy from glucose?

No copying 15 pts how does a free-body diagram tell you about the net force on an object?