Of all the species that have ever lived on Earth, how many have gone extinct?
a. less than 1%
b. about 10%
c. about 25%
d. about 75%
e. about 99%
ANSWER: e
You might also like to view...
Skeletal muscle contraction begins when calcium ions bind to _____
A) energized cross-bridges B) myosin C) actin D) acetylcholine receptors E) troponin
Freshwater fish are in a hypotonic environment. What keeps the cells in their body from lysing?
A. Freshwater fish have chloride channels that actively move chloride out of the gills into the surrounding water, allowing water to move into the gills. B. Freshwater fish have chloride channels that actively move chloride out of the gills into the surrounding water, allowing water to move out of the gills. C. Freshwater fish have chloride channels that actively move chloride into the gills, allowing water to move into the gills. D. Freshwater fish have chloride channels that actively move chloride into the gills, allowing water to move out of the gills.
Paul Ehrlich used chemotherapy to treat
A) cholera. B) cancer. C) anthrax. D) smallpox. E) syphilis.
Living as a member of a group may have all of the following advantages except what?
A. More individuals scan the environment for dangers B. Increased feeding rate C. Being more resistant to disease and parasites D. Greater protection from predators E. Members learn about new food sources from other members