Even though the autumn may be unusually
warm, the leaves from deciduous trees begin to
drop during September. Which of the
following is the best explanation?
a. The trees are responding to shorter days.
b. The autumn months are usually drier
because the summer rains have tapered off.
c. The effects of phototropism are operating
"right on schedule."
d. There is not enough sunlight to carry on
photosynthesis any longer.
e. None of these are the best explanation
A
You might also like to view...
If a cell were unable to produce histone proteins, which of the following would be a likely effect?
A) There would be an increase in the amount of "satellite" DNA produced during centrifugation. B) The cell's DNA couldn't be packed into its nucleus. C) Spindle fibers would not form during prophase. D) Amplification of other genes would compensate for the lack of histones.
Which of the following statements is FALSE
about energy in molecules?
a. Chemical bonds in molecules contain energy. b. Reactants always have less energy than products. c. Some molecules contain more energy than others. d. Molecules release energy when they react with oxygen. e. When broken, chemical bonds release energy.
A severely injured animal is able to still able to
defend itself due to the action of ___.
a. dopamine b. endorphins c. serotonin d. acetylcholine e. GABA
The relationship between photosystem I (PSI) and photosystem II (PSII) is correctly described by which of the following statements?
A) PSI precedes PSII in photosynthesis. B) Electrons are excited by PSI or PSII, but not both. C) Chlorophyll molecules in the reaction centers of PSI and PSII are designated P700 and P680, respectively, to reflect the wavelengths of their light absorption maxima. D) PSII was discovered before PSI. E) Only PSI contains a special pair of chlorophyll a molecules.