In prokaryotes, the genes for metabolic pathways are
a. always on for early steps in the pathway, but genes for later steps are generally off.
b. always on so the bacteria can respond rapidly to changing conditions.
c. turned on and off as conditions change.
d. independently regulated.
e. expressed in low levels all of the time, but will be expressed in higher levels when
conditions warrant.
C
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A short-lived contraction of the cells in a motor unit is known as a
a. muscle twitch. b. tetanus response. c. spasm. d. contracture. e. treppe.
Living as a member of a group may have all of the following advantages except what?
A. increased feeding rate B. members learn about new food sources from other members C. greater protection from predators D. more individuals scan the environment for dangers E. being more resistant to disease and parasites
What is true of the Shannon diversity index? Select all that apply.
_____ Within a community, Its value increases as the number of species sampled increases. _____ Its value is independent of species relative abundance. _____ It does not take into account very rare species. _____ Its value increases when individuals are more evenly distributed among species
Red tide and extensive fish kills are caused by population blooms of
a. euglenoids. b. dinoflagellates. c. diatoms. d. ciliates. e. brown algae.