Question

which of the following shows the base - pairing rules in a dna molecule? adenine pairs with guanine; cytosine pairs with thymine adenine pairs with cytosine; guanine pairs with thymine adenine pairs with thymine; cytosine pairs with guanine adenine pairs with uracil; cytosine pairs with guanine question 4 1 pts what holds one strand against the other in the double helix? hydrogen bonds covalent bonds ionic bonds van der waals forces

Explanation:

• For the base - pairing question:
• In DNA, adenine (A) pairs with thymine (T) through two hydrogen bonds, and cytosine (C) pairs with guanine (G) through three hydrogen bonds. This is a fundamental rule of DNA structure.
• For the bond - holding - the - double - helix question:
• The two strands of the DNA double helix are held together by hydrogen bonds between the complementary base pairs. Covalent bonds are within the sugar - phosphate backbone of each DNA strand. Ionic bonds are not the main force holding the two strands together. Van der Waals forces are relatively weak and not the primary force for holding the double - helix structure compared to hydrogen bonds.

Answer:

• For the base - pairing question: adenine pairs with thymine; cytosine pairs with guanine
• For the bond - holding - the - double - helix question: Hydrogen bonds