Question

1. the leading | lagging strand is made in okazaki fragments.
2. how does the bonding in dna allow the strands of dna to open up for replication?

Explanation:

For question 18, during DNA replication, the lagging strand is synthesized discontinuously as Okazaki fragments. The leading strand is made continuously.
For question 19, DNA has hydrogen bonds between complementary base pairs (A - T, C - G). These hydrogen bonds are relatively weak compared to covalent bonds. Enzymes like helicase can break these hydrogen bonds, allowing the two strands of DNA to separate (open up) so that each strand can serve as a template for replication.

Answer:

1. lagging
2. DNA has hydrogen bonds between base - pairs. Helicase breaks these hydrogen bonds to open the strands for replication.