Studies have shown that in the flowering plant Arabidopsis the root-shoot axis is established ____
a. by the first cell division of the embryo
b. within hours after the seed germinates
c. during the torpedo stage of embryonic development
d. shortly after the eight-cell embryo stage
e. by plant tissues breaking through the seed coat and making contact with soil
ANSWER: a
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A few bacteria are capable of growing on gases as the sole source of energy, carbon, and nitrogen. Which of the following combination of gases would support the growth of a bacterium in mineral media with NO other additions?
A) H2, N2, CO2 B) H2, O2, N2, CO2 C) H2, H2S, N2, CO2 D) H2, O2, N2O, CO2
Which of the following is NOT associated with
Marfan syndrome?
a. skin lacking elasticity b. loose joints c. weakened aorta d. short stature e. mutated fibrillin gene
DNA is contained in the _____ of the cell nucleus.
a) proteins b) cytoplasm c) chromosomes d) RNA
During REM sleep, an EEG shows
A) a flat trace with very few waves. B) a pattern that is similar to when a person is in deep sleep. C) an irregular, rapidly changing pattern.