(C) to direct sailing studies
(D) studies direct sailing
5. ______ social nesting birds that built their nests in trees and on cliffs.
(A) The most storks
(B) Most are storks
(C) Most storks are
(D) Storks most
6. Plankton, ______, is the basic foodstuff for everything that lives in the ocean.
(A) comprise both minute marine animals and plants
(B) is the name given to minute marine animals and plants
(C) the collective name for minute marine animals and plants
(D) minute marine animals and plants collectively that
7. The best-known diffuse nebula is the great Orion Nebula, _______ can be seen by the
naked eye.
(A) one
(B) it
(C) which
(D) who
8. Of all the economically important plants, palms have been ______.
(A) the least studied
(B) study the least
(C) study less and less