1) The 32 species that make up the dolphin family are closely related to whales and in fact include the animal known as the killer whale, which can grow to be 30 feet long and is famous for its aggressive hunting pods.

A. include the animal known as the killer whale, which can grow to be 30 feet long and is
B. include the animal known as the killer whale, growing as big as 30 feet long and
C. include the animal known as the killer whale, growing up to 30 feet long and being
D. include the animal known as the killer whale, which can grow as big as 30 feet long and is
E. include the animal known as the killer whale, which can grow to be 30 feet long and it is

2) Soaring television costs accounted for more than half the spending in the presidential campaign of 1992, a greater proportion than it was in any previous election.

A. a greater proportion than it was
B. a greater proportion than
C. a greater proportion than they have been
D. which is greater than was so
E. which is greater than it has been

3) To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.

A. have to know a great deal more than now about the social and economic
B. have to know a great deal more than they do now about the social and economical
C. would have to know a great deal more than they do now about the social and economical
D. would have to know a great deal more than they do now about the social and economic
E. would have to know a great deal more than now about the social and economical

Plz help with ur explanations.