He Earth is constantly spinning on its axis, like you might spin a basketball on your finger.

It is this spinning of the Earth that causes
A) the summer-time heat.
B) the need for a leap year.
C) the changes in the seasons.
D) the cycle of night and day.

the cycle of night and day

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Explanation:

a few examples of ethical concerns involving genetically engineering of humans include

-privacy of genetically tested people

- potential side effects

-long term effects

blue stars have the highest surface temp

stellar distances are usually expressed in light-years

the measure of a star's brightness is called magnitude

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