**PLEASE ANSWER ASAP**
Which of the following statements about Earth's atmosphere is true?

a) The atmosphere exerts greater downward than upward pressure.

b) Pressure is highest in upper areas of the atmosphere.

c) Atmospheric pressure increases as altitude decreases.

d) Pressure is equal at all levels of the atmosphere.

Of the groups of elements below, which are most likely to gain electrons to become anions? a. alkali metal b. boron group c. halogen d. transition metal

Match the following vocabulary terms to their definitions. 1. amount of energy required to change 1 gram of material from the solid to the liquid state at its melting point 2. a measure of the kinetic energy of the particles of a substance 3. the amount of heat energy required to raise the temperature of 1 gram of liquid water from 14.5°c to 15.5°c 4. amount of energy required to change 1 gram of material from the liquid to the gaseous state at its boiling point 5. the amount of energy required to change 1 gram of a substance 1°c a. temperature b. latent heat of vaporization c. latent heat of fusion d. calorie e. specific heat

What is a metal replacement reaction