The greatest extinction event of all time occurred at the end of the:
A) Cambrian period. B) Permian period. C) Mesozoic era. D) Cretaceous period.
Answer: B
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The appearance of Pax-6 in all animals with eyes can be explained in multiple ways. Based on the information above, which explanation is most likely?
A) Pax-6 in all of these animals is not homologous; it arose independently in many different animal phyla due to intense selective pressure favoring vision. B) The Pax-6 gene is really not one gene. It is many different genes that, over evolutionary time and due to convergence, have come to have a similar nucleotide sequence and function. C) The Pax-6 gene was an innovation of an ancestral animal of the early Cambrian period. Animals with eyes or eyespots are descendants of this ancestor. D) The need for eyes has resulted in the separate evolution of Pax-6 genes.
In dietary terms, a "complete" protein is one that:
a. can serve in a variety of cellular functions, like as an enzyme, oxygen transporter, etc. b. contains all of the essential amino acids. c. contains carbohydrates, lipids, and nucleic acids as well. d. stays intact as it travels through your digestive system. e. contains all 20 amino acids.
A freshwater protozoan, such as Paramecium, tends to ________ because it lives in a ________ environment
A) lose water; hypertonic B) gain water; isotonic C) lose water; hypotonic D) gain water; hypotonic E) gain water; hypertonic
Cilia from sensory cells that detect motion are located within the
A. cochlea. B. upper nasal cavity. C. interior eye. D. semicircular canals.