For the first 2 billion years of its history, Earth's atmosphere lacked (or had very little) oxygen. Which of the following organisms produced much of the oxygen that now makes up the current atmosphere of Earth?
A. hyperthermophiles
B. cyanobacteria
C. anoxygenic photosynthetic bacteria
D. euryarchaeota
B
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You are studying a disease caused by insufficient levels of a specific peptide hormone, and characterize mutations in several genes that can lead to the disease. Your startup company can only afford to pursue one gene product as a possible therapy. Which would you choose?
A. Gene A -- a transcription factor. B. Gene B -- an enzyme that activates the hormone by cleaving its inactive precursor. C. Gene C -- the hormone itself. D. Gene D -- a kinase that acts downstream of the hormone. Clarify Question What is the key concept addressed by the question? What type of thinking is required? Gather Content What do you already know about hormones? What other information is related to the question? Choose Answer Given what you now know, what information is most likely to produce the correct answer? Reflect on Process Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
Explain how species that are not closely related can look or behave so similarly. Give an example
What will be an ideal response?
Which statement is not true about conifers?
a. Conifers are gymnosperms. b. All conifers belong to the genus Pinus. c. All conifers have naked seeds. d. Conifers are heterosporous.
Which endocrine gland regulates the overall metabolic rate of the body, as well as playing a role in calcium homeostasis?
a. pituitary
b. adrenal
c. thyroid
d. parathyroid