The accepted explanation for the disappearance of the dinosaurs is _____
a. the result of an asteroid impact
b. the loss of food sources
c. competition by mammals
d. gas emissions from volcanoes
e. giant tsunamis caused by earthquakes
ANSWER: a
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The anterior pituitary hormone which has a generalized effect, having receptors on almost every cell in
the body, is
a. prolactin. b. growth hormone. c. gonadotropin. d. ADH. e. ACTH.
Which grouping includes all of the protists?
A. Kingdom Plantae B. Domain Eukarya C. Kingdom Animalia D. Domain Archaea
In a biology lab exercise, you are asked to examine cells of a growing onion root tip that has been sectioned to show many cells. In most of the cells, you easily see the circular or oval nucleus as a uniformly filled space in a membrane outline. In a small percentage of cells, you see chromosomes as distinct strands just as cell division begins, and as it progresses, because the chromatin
A. becomes less tightly wound, to facilitate cell division.
B. increases in length, as replication adds DNA sections to the original.
C. becomes more tightly folded, increasing their visible length.
D. becomes less tightly folded, increasing their visible length.
E. becomes more tightly wound, to protect DNA, and to more easily manage cell division.
Insects have a(n) __________ eye, with many individual units. Fill in the blank(s) with the appropriate word(s)