Question

algae: the biofuel of tomorrow
an algae farm needs space, saltwater, carbon dioxide, and exposure to continuous,
direct sunlight (17) these essentials require a lot of money, which necessitates a
literal investment in the future of the technology, and investors aren’t easily
persuaded to hand over their money.
5 (18) here, we have a large supply of unused, sunbathed land—particularly in the
central and western states. (19) even for farmers who currently grow traditional crops
such as wheat, corn, and soy, algae farming may be an attractive option for part of
their land for a variety of reasons. (20) algae crops are sustainable; in fact, a corn
farm might produce one harvest a year, while an algae farm might produce a
harvestable crop every few weeks. (21) not only does algae eat climate - changing
carbon dioxide, but it also yields life - giving oxygen as a by - product.
6 (22) as you can see, these facts are very compelling. (23) our human dependence
on petroleum will have to end one way or another: we’ll either replace the tired,
damaging addiction to coal with a new, more sustainable and earth - friendly
technology, or we’ll simply exhaust the planet’s supply of petroleum without having a
replacement. (24) it is worthwhile to invest in that replacement today and secure a
more energy - stable future. (25) perhaps algae will be america’s green gasoline.
question 16
dwayne would like to improve the closing paragraph by replacing sentence 22.
which of the following could best replace sentence 22 and help strengthen the
paper’s conclusion?
a. as you can see, algae farms are not the solution.
b. ladies and gentlemen, there is a possible choice in alternative energies of
the future.
c. in closing, many believe that it is time to acknowledge the promise of algae
and to invest in its future.
d. at the end of the day, even proponents of petroleum will choose algae over
their dying industry.

Explanation:

The text discusses the potential of algae as a biofuel, its advantages (sustainable, can be harvested multiple times a year, uses unused land in central and western states, helps with carbon dioxide, etc.), and the need for investment. Sentence 22 ("As you can see, these facts are very compelling. (23) Our human dependence on petroleum will have to end one way or another: we’ll either replace the tired, damaging addiction to coal with a new, more sustainable and earth - friendly technology, or we’ll simply exhaust the planet’s supply of petroleum without having a replacement. (24) It is worthwhile to invest in that replacement today and secure a more energy - stable future. (25) Perhaps algae will be America’s green gasoline.") is about the conclusion that algae could be a solution (replacement for petroleum) and the need for investment. Option C ("In closing, many believe that it is time to acknowledge the promise of algae and to invest in its future.") best captures this conclusion as it ties together the idea of algae's promise (from the discussed facts) and the call for investment (similar to the sentiment of sentences 24 - 25 which are part of the conclusion in the text).

Answer:

C. In closing, many believe that it is time to acknowledge the promise of algae and to invest in its future.