Heart excitation originates in the
a. atrioventricular node.
b. intercalated disk.
c. sinoatrial node.
d. pericardium.
e. endothelium.
Answer: c
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If a special fungicide killed all of the glomeromycetes in an environment, but did not affect other types of fungi, which of the following would most likely occur?
A. Plant nutrient uptake from the soil would be reduced. B. Overall decomposition rates would be dramatically reduced. C. Mushrooms would be absent from the environment. D. Lichens would be absent from the environment. E. Aquatic habitats would completely lack fungi.
Cell-cycle checkpoints temporarily block key events from being initiated during the cell cycle
__________________ Indicate whether the statement is true or false.
A plant's lateral roots arise from the
a. endodermis b. epidermis c. phloem d. xylem e. pericycle
This process reproduces many varieties of fruit trees and other plants by making cuttings of the plant and rooting the cuttings.
A. cloning B. sexual reproduction C. meiosis D. somatic cell transfer