The valves in the heart open and close to move blood in between heart chambers. O a) three directions O b) two directions O c) four directions d) one direction

Hi,

The valves in the heart open and close to move blood in between heart chambers.

d) one direction

the largest known star in the universe is uy scuti, a hypergiant with a radius around 1,700 times larger than the sun.jul 26, 2018

explanation:

freezing

deposition

condensation

explanation;

melting also called fusion is the process where solid becomes liquid, sublimation is the process where solid becomes gaseous without first changing to liquid, deposition involves change from gaseous to solid state, freezing involves change from liquid to solid, boiling or evaporation involves change of liquid to gaseous state, while condensation is the change from gaseous state to liquid state.

endothermic reactions involves absorption of heat from the surroundings or the environment while exothermic reactions involves loss of heat energy to the surroundings.

in this case, sublimation, evaporation and melting are endothermic reactions (gain energy from the environment) while, freezing, deposition and condensation are exothermic (loss of energy to the surroundings) reactions.