The chemical composition of the gases surrounding the Earth has changed substantially over the past 4 billion years. One notable change was due to the emergence of organisms that photosynthesized. Their photosynthesis increased the amount of which of the following gases in the atmosphere?
A. Carbon dioxide (CO2).
B. Nitrogen (N2).
C. Hydrogen sulfide (H2SO4).
D. Oxygen (O2).
E. Water vapor (H2O).
D. Oxygen (O2).
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The hormonal control over excretion most likely occurs in the
a. Bowman's capsule. b. proximal tubule. c. distal tubule. d. loop of Henle. e. urinary bladder.
What is a potential problem with the use of transgenic varieties of plants that contain Bt toxin?
A) Bt toxin may be harmful to humans. B) Bt toxin may be harmful to some beneficial insects. C) Transgenic crop varieties with Bt toxin are not very hardy and require a lot of care. D) Transgenic crop varieties with Bt toxin require large amounts of chemical insecticides to grow.
Most somatic cells (regular cells) in your body replicates through a cell division process called __________.
A. sex differentiation B. mitosis C. dimorphic cell division D. meiosis
RNA polymerase II of eukaryotes always requires more than one general transcription factor to initiate transcription.
Answer the following statement true (T) or false (F)