Now extinct, tooth parts of ____ are abundant as fossils dating from the early Paleozoic to the early
Mesozoic era. These jawless fishes are considered to be the earliest vertebrates with bonelike
structures.
a. acanthodians
b. conodonts
c. osteolepiforms
d. placoderms
e. ostracoderms
B
You might also like to view...
A chemical reaction that has a positive ?G is best described as _____
A) endergonic B) entropic C) enthalpic D) spontaneous E) exergonic
Increased heart rate and blood pressure and unusually heavy sweating are symptoms of
a. hyperthyroidism. b. Grave's disease. c. acromegaly. d. hypothyroidism. e. Wilson's disease.
During Krebs cycle reactions the ____________________ NAD and FAD pick up H+ and electrons for processing in
the electron transport system. Fill in the blank(s) with the appropriate word(s).
An individual plant was discovered that could not grow towards light. After some research, it was determined that the reason was a defective gene that did not allow for the level of cell elongation necessary for a phototropic response. This mutation greatly reduces the fitness of the individual plant. Which reason best describes the reason for the loss of fitness?
A) The plant was too short to attract insects for pollination. B) The plant could not adjust to directional light, which reduced photosynthetic activity and therefore energy available for reproduction. C) Because the plant grew much taller and straighter, resources that could be used for reproduction were used for growth. D) The loss of a phototropic response meant that the plant's seeds could not germinate so reproduction would be unsuccessful.