The structure that helps assure that only a single sperm fertilizes an egg is the
A. placenta.
B. zona pellucida.
C. blastocyst.
D. amnion.
Answer: B
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Which of the following describes what happens to the height of the column in a mercury barometer when surface air pressure decreases?
A. It increases. B. It decreases. C. It changes momentarily, but returns to its earlier reading. D. It remains constant.
__________ is the world's leading industry of the early 2000s and provides one of the most significant connections between globalization and development.
Fill in the blank(s) with the appropriate word(s).
Scoria cones form from repeated eruptions over the course of many decades.
Answer the following statement true (T) or false (F)
________ rock has undergone heat or pressure, causing it to change form
A) Sedimentary B) Deformative C) Igneous D) Conglomerate E) Metamorphic