Answer to Question 1The gravitational pull of the Moon on Earth pulls the water toward it, creating a bulge at the nearest
point. Another bulge forms on the opposite side of Earth due to the centrifugal force of Earth's
rotation. These two bulges point toward and away from the Moon, and between the two bulges are two
troughs since the water is in the bulges. The bulges are high tides, and the troughs are low tides. Earth
rotates beneath them, and most shorelines on Earth reach each one once a day, and so have two high
tides and two low tides each day.
Answer to Question 2The tides are caused by the gravitational attraction of the Moon and Sun on the ocean surface. The
Moon exerts a stronger force because, although the Sun is 27 million times more massive than the
Moon, it is 390 times as far from Earth. Consequently, the Sun exerts a tide-generating force only 46
as strong as the Moon's.
(a) With few ticks, moose retain a brown coat; (b) at high numbers of ticks, moose self-groom, destr
Male giraffe mounting a female. Only dominant males are generally able to mate.
Bipolar disease. The term bipolar means “pertaining to two poles.” The individual with this form of
In some species, dominant females have more surviving offspring that mature earlier indicating an ad
Selected High-Risk Drugs for Older Adults
The diminishing effects on body weight of a low-calorie diet and a high-calorie diet.