Which of the following causes high and low tides on earth? a. the moon's gravitational pull on earth causes water to bulge on two sides of the earth. b. water swells when tsunamis occur in two areas of earth at the same time. c. the earth's rotation is so fast, water will swell and shrink twice a day. d. the earth is tilted on an axis, causing water to spread unevenly throughout the planet.

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substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.