“There are specialists in each habitat, but there is also
overlap,” What does the author mean by “specialists”?

How does this differ from the ordinary use of the word?

Which is a run-on sentence? a) all of the fish that we caught were too small to keep. b) ricky changed the oil, he forgot to replace the oil filter. c) the striking patriotic design surprised the memorial planning committee. d) everyone on the harbor cruise reported feeling a little seasick and left early.