CE
Chief Editor
Mar 17, 2024
Practice Quiz Mode
Take all 5 MCQs in interactive quiz mode with timer and progress tracking
The Alvarez theory, developed in 1980 by physicist Luis Walter Alvarez and his geologist son Walter Alvarez, maintained that the secondary effects of an asteroid impact caused many dinosaurs and other animals to die ________ it left unexplored the question of whether unrelated volcanic activity might have also contributed to the mass extinctions.
Which choice completes the text so that it conforms to the conventions of Standard English?
Difficulty: Easy
A:
out but
B:
out, but
C:
out
D:
out,
A pioneer in the field of taphonomy (the study of how organic remains become fossils), ________ may be just as prevalent in the fossil record as those of thick-shelled organisms.
Which choice completes the text so that it conforms to the conventions of Standard English?
Difficulty: Medium
A:
fossils of thin-shelled organisms, Anna Behrensmeyer demonstrated in a 2005 analysis,
B:
Anna Behrensmeyer demonstrated in a 2005 analysis that fossils of thin-shelled organisms
C:
it was demonstrated in a 2005 analysis by Anna Behrensmeyer that fossils of thin-shelled organisms
D:
a 2005 analysis--by Anna Behrensmeyer--demonstrated that fossils of thin-shelled organisms
Because a cycle of lunar phases ________ 29.5 days to complete, it's possible to observe two full moons in a single month, one at the beginning and one at the end.
Which choice completes the text so that it conforms to the conventions of Standard English?
Difficulty: Medium
A:
are taking
B:
have taken
C:
take
D:
takes
The alga species Chlorella vulgaris is very efficient at making oxygen. For this reason, scientists are currently exploring ways to use this species in space. C. vulgaris might be used, for example, to build future biological air exchange systems that ________ oxygen for astronauts.
Which choice completes the text so that it conforms to the conventions of Standard English?
Difficulty: Easy
A:
are producing
B:
produced
C:
produce
D:
have produced
Researchers studying magnetosensation have determined why some soil-dwelling roundworms in the Southern Hemisphere move in the opposite direction of Earth's magnetic field when searching for ________ in the Northern Hemisphere, the magnetic field points down, into the ground, but in the Southern Hemisphere, it points up, toward the surface and away from worms' food sources.
Which choice completes the text so that it conforms to the conventions of Standard English?
Difficulty: Hard
A:
food:
B:
food,
C:
food while
D:
food
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