During peristalsis a. muscles contract voluntarily to move food in one direction

b. muscles contract voluntarily to move food up and down the esophagus

c. muscles contract involuntarily to move food up and down the
esophagus

d. muscles contract involuntarily to move food in one direction

Explanation:

Reorder the terms:

8 + 6p + -4p = 3(p + 4)

Combine like terms: 6p + -4p = 2p

8 + 2p = 3(p + 4)

Reorder the terms:

8 + 2p = 3(4 + p)

8 + 2p = (4 * 3 + p * 3)

8 + 2p = (12 + 3p)

Solving

8 + 2p = 12 + 3p

Solving for variable 'p'.

Move all terms containing p to the left, all other terms to the right.

Add '-3p' to each side of the equation.

8 + 2p + -3p = 12 + 3p + -3p

Combine like terms: 2p + -3p = -1p

8 + -1p = 12 + 3p + -3p

Combine like terms: 3p + -3p = 0

8 + -1p = 12 + 0

8 + -1p = 12

Add '-8' to each side of the equation.

8 + -8 + -1p = 12 + -8

Combine like terms: 8 + -8 = 0

0 + -1p = 12 + -8

-1p = 12 + -8

Comb

sea breeze

explanation:

cool air is going towards land allowing for the land to be cooler, the hotter air gets pushed away from the land.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.