The strand of the opened DNA is easily replicated, but the strand must be replicated in pieces because of its orientation. a. bottom; top
b. lagging; leading
c. leading; lagging
d. top; bottom

c. leading; lagging

Explanation:

This question s describing the process of DNA replication, which is the process by which DNA forms an identical copy of itself. The process of DNA replication is carried out majorly by an enzyme called DNA polymerase. After which the double stranded DNA has been unwound by DNA helicase, two single strands results.

One of these strands runs in the 3'-5' direction called LEADING STRAND while the other runs in the 5'-3' direction called LAGGING STRAND. However, because replication by DNA polymerase proceeds in the 5'-3' direction, the LEADING strand of the opened DNA is easily replicated, but the LAGGING strand must be replicated in pieces called OKAZAKI FRAGMENTS because of its orientation.

a covalent bond, specfically triple bond

69 is the correct math for the amino acids