The evolution of photosynthetic organisms required a source of hydrogen for the synthesis of complex, high-energy molecules. What is the source of hydrogen for today's photosynthetic organisms?
a. sugar
b. water
c. amino acids
d. hydrogen sulfide
e. air
Ans: b. water
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Which of the following statements regarding gonorrhea is incorrect?
A. Pelvic inflammatory disease (PID), epididymitis, and infertility are complications. B. It is a sexually transmitted infection. C. Females can have asymptomatic infections. D. A chancre-type lesion develops at the portal of entry. E. Symptoms include painful urination and discharge.
The outer membranes of bacteria, mitochondria, and chloroplasts contain large nonselective channels made of multipass proteins known as ________ in which the transmembrane segment of the protein is composed of a ________
Fill in the blank with correct word.
During a controlled experiment, a scientist isolates and tests
A) a control group. B) a conclusion. C) a single variable. D) a mass of information.
The largest annual movement of carbon between reservoirs occurs ____.
A. from plants to atmosphere B. from soil to atmosphere C. from atmosphere to ocean D. from atmosphere to plants E. from ocean to atmosphere