Read the passage and answer the question that follows.

scientists generally agree that earth is getting warmer due to what's called the greenhouse effect. a greenhouse used for plants stays warm because sunlight and heat coming through the glass roof are mostly trapped. the heat doesn't radiate back into the atmosphere because it's partly trapped by the glass. something like that happens on earth. the atmosphere acts like a blanket that keeps the sun's heat from leaking away into space.

the main conclusion you can draw from this paragraph is that

a. in a greenhouse, the sun's heat is trapped by the glass.
b. a greenhouse plants to grow faster.
c. because of the greenhouse effect, plants on earth should thrive.
d. the atmosphere keeps earth warm.

[1] nothing that comes from the desert expresses its extremes better than the unhappy growth of the tree yuccas. tormented, thin forests of it stalk drearily in the high mesas, particularly in that triangular slip that fans out eastward from the meeting of the sierras and coastwise hills. the yucca bristles with bayonet-pointed leaves, dull green, growing shaggy with age like an old [5] man's tangled gray beard, tipped with panicles of foul, greenish blooms. after its death, which is slow, the ghostly hollow network of its woody skeleton, with hardly power to rot, makes even the moonlight fearful. but it isn't always this way. before the yucca has come to flower, while yet its bloom is a luxurious, creamy, cone-shaped bud of the size of a small cabbage, full of sugary sap. the indians twist it deftly out of its fence of daggers and roast the prize for their [10] own delectation why does the author use the words "bayonet-pointed" (line 4) and "fence of daggers" (line 9) to describe the leaves of the yucca tree? . to create an image of the sharp edges of the plant to emphasize how beautiful the plant's leaves are to explain when and where the plant grows to show how afraid the author is of the plant

Which statement is an example of a complex sentence? a. although he denies them, dr. vasquez faced several scandals last year. b. people tend to use too many clauses in sentences that should be simple. c. cars tend to be expensive, but airplanes are in a price range of their own. d. i am in favor of proposition 1, and i am also in favor of proposition 16.

Amajor change to biographies that began in the 16th century was that they