Substances that contain two or more elements in a fixed ratio are called _____.
A. isotopes
B. cells
C. matter
D. compounds
D. compounds
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What region in eukaryotic genes usually contains the majority of regulatory elements?
A. 0 to 50 B. -50 to 0 C. -50 to -100 D. -100 to -150
Which of the following statements is TRUE?
a. Ion channels are primarily composed of fatty acids. b. Usually both sodium and potassium can move through the same ion channel. c. Membranes are usually slightly positively charged on the inside. d. The electrical gradient in most cells tends to push K+ out of the cell, through open channels. e. Channel gating can be regulated by the membrane potential.
Plant pathogens that produce chestnut blight, Dutch elm disease, and apple scab belong to which fungal group?
a. Ascomycota b. Microsporidia c. Zygomycetes d. Basidiomycetes e. Chytrids
Humans become infected with Toxoplasma gondii primarily by
A) being bitten by a tick. B) direct skin penetration. C) ingesting food or water contaminated with cysts. D) ingesting meat containing the parasite. E) intimate contact with another person.