Here is a sketch of an incomplete replication fork, as might be seen in e. coli.
at which letter—(a), (b), (c), (d), or a combination of letters—would you expect to see the more continuous synthesis of dna (the leading strand)?
a. (a)
b. (b)
c. (c)
d. (d)
e. (b) and (c)

The question is missing some parts.

Leading strand synthesis proceeds continuously in the 5' to 3' direction, keeping pace with the replication fork.

Explanation: DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules. Replication is important because, whenever a cell divides, the two new daughter cells must contain the same genetic information, or DNA, as the parent cell.

DNA replication in E. coli initiates at oriC, the origin of replication and proceeds in two directions, resulting in two replication forks that travel in opposite directions from the origin.  

The DNA Replication process can be divided into three stages: Initiation, Elongation, and Termination.

The key component in the initiation process is the Dna.A protein which recognizes and successfully denatures the DNA in the region of the 13 base pairs repeats, which are rich in A=T pair.

The elongation phase of replication consists of Leading strand synthesis and Lagging synthesis.

Leading strand synthesis:

It begins with the synthesis by “Primase” of a short (10 to 60 nucleotide) RNA primer at the replication origin. Deoxyribonucleotides are then added to this primer by DNA polymerase-III. Once begun, leading strand synthesis proceeds continuously in the 5' to 3' direction, keeping pace with the replication fork.

Lagging strand synthesis:

It must be accomplished in short fragments (Okazaki fragments) synthesized in the direction opposite ( discontinuously in the 3' to 5' direction) to the fork movement.

Each fragment must have its own RNA primer synthesized by “primase”, and positioning of the primers must be controlled and coordinated with fork movement.

When the new Okazaki fragment is complete, the RNA primer is removed by DNA polymerase-I and is replaced with DNA by the same enzyme. The remaining nick is sealed by “DNA ligase”.

Termination is the last stage which brings replication to an end. It occurs in the termination zone.

P.S. Image courtesy of quora.com

false because ozone (o3) depletion does not cause global warming, but both of these environmental problems have a common cause: human activities that release pollutants into the atmosphere altering it.

global warming is caused primarily by putting too much carbon dioxide into the atmosphere when coal, oil, and natural gas are burned to generate electricity or to run our cars.

explanation: