What interactions contribute the most to holding the two strands of dna together?

Explanation:

The DNA double helix (both strands of DNA) are  held closs together by i) mainly hydrogen bonds between complementary bases  and ii) the Van der Waals base-stacking interaction.

The hydrogen bonds between the base pairs form the double helical structure of DNA. There is no exchange or sharing of electrons in hydrogen bonds.

G always pairs with C with three hydrogen bonds and T always pairs with A with two hydrogen bonds.

Explanation:

In DNA double helix structure , there's four nitrogen bases Adenine , Thymine, Cytosine and Guanine . Hydreogen bonds formed between these nitrogenous base in DNA . In DNA double helix , two hydrogen bonds exist between Adenine and Thymine while three hydrogen bond exist between Cytosine and Guanine . Pairing of nitrogen bases in DNA double helix is very specific and this specific and selective pairing results in 'complementary base pairing ' .  Hydrogen bonds doesn't involve in sharing of electrons , it occur over short distance and it can be formed and broken easily . In DNA double helix , hydrogen bond  is weaker but still contribute the most to holding the two strands of DNA together because hydrogen bonds present excessively in between the DNA double helix .

he movement of air through earth's or any planet's atmosphere is called wind, and the main cause of earth's winds is uneven heating by the sun. this uneven heating causes changes of atmospheric pressure, and winds blow from regions with high pressure to those with low pressure.

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