A skateboarder pushes the ground with one foot, and moves forward. Which statement BEST explains his motion?
The mass of the skateboard decreased causing acceleration to move him forward.
The unbalanced force exerted by the skateboarder’s foot caused him to move forward.
The mass of the student and skateboard increased causing acceleration to move him forward.
The balanced forces on the skateboard allowed it to change his motion and move him forward.

D because to ride a skateboard you need balance to move you forward or you will fall

The horse latitudes-high-pressure zones about 30 degrees north and 30 degrees south of the equator.-warm air traveling away from the equator cools and sinks-weather tends to be clear and drythe doldrums-low-pressure near equator-air rises and spreads out toward the poles-rising moist air produces clouds and heavy rainthe westerlies-blow from the west-move from the horse latitudes toward the poles.-bring storms across much of the united statesthe tradewinds-blow from the east-move from the horse latitudes toward the equator  -strong, steady winds