A DNA molecule consists of two stands of nucleotides that wind around each other like a twisted ladder with a phosphate and sugar backbone. The nitrogenous bases are divided into two groups called the pyrimidines and the purines. The pyrimidines include the thymine and cytosine, the purines are adenine and guanine. The nitrogenous bases in the double helix are bound together according to the base pairing rule. Adenine pairs with thymine (A-T) and guanine pairs with cytosine (G-C). The student either drew the base pairing showing adenine and thymine or guanine pairing with cytosine.
The first option is correct.
Earth always has two surrounding gravitational forces, one proceeding from the moon and one from the sun.
The sun's pull, despite the fact our sun is further then the moon, is stronger and creates the high tide, and the moon the low tide. But as we know our earth moves, now exposing the other side to the sun which in turn leaves the other side of earth with the high tides and the other with the low tides. Tides never move, what moves is earth.
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Happy homework/ study/ exam!
I thing the correct answer is d
