Which of the following statements is false?
A. Differentiation of distinct cell types was a
key step in the evolution of complex
multicellularity.
B. Complex multicellularity involves
differentiation in space instead of time.
C. Unicellular organisms can have life cycles
where different cell types alternate in time.
D. Distinct cell fates are achieved by
switching on and off different combinations of
genes in different cells.
E. Gradients of environmental signals trigger
differentiation of cells.
A
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Except that they are not produced in the cytoplasm, conidia produced by Streptomyces spp. are chemically quite similar in composition to endospores produced by Bacillus spp
Indicate whether the statement is true or false.
Colon cancer is the second most common type of cancer in the United States, second only to
a. lung cancer. b. breast cancer. c. skin cancer. d. prostate cancer. e. uterine cancer.
The general term used to denote a situation in which two organisms live together in a close partnership required by one or both members is ______.
A) Antibiosis B) Synergy C) Mutualism D) Symbiosis
How do temporal and spatial summation improve the processing power of the brain?
A. Temporal and spatial summation both make the neuron more likely to fire action potentials. B. Temporal summation allows circadian rhythms to regulate neuronal activity. Spatial summation allows latitude to regulate neuronal activity. C. Temporal summation allows a neuron to fire prolonged action potentials, and spatial summation allows a neuron to synapse onto new targets. D. Temporal summation allows a neuron to recognize a persistent signal from a single presynaptic cell, and spatial summation allows a neuron to recognize a broad signal from multiple presynaptic cells.