The openings in the exoskeleton of arthropods that allow oxygen into highly branched internal tubules that reach individual body cells are

A. spicules.
B. alveoli.
C. tracheae.
D. spiracles.
E. gills.


D. spiracles.

Biology & Microbiology

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Do different types of teeth have different functions?

a. Yes b. No

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Although pyruvate is the end product of glycolysis and no more ATP is generated by fermentation of pyruvate to ethanol, yeast produce ethanol under anaerobic conditions because

A) pyruvate export requires more energy than ethanol export. B) electrons (and protons) are then added to ethanol to make lactate. C) transfer of electrons from NADH to pyruvate to make ethanol regenerates NAD+, which is necessary for new rounds of glycolysis to proceed. D) glycolysis substrate-level phosphorylation changes pyruvate to ethanol. E) pyruvate to ethanol fermentation decreases deleterious CO2 levels.

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Most communities have many common species and a few rare species

Indicate whether the statement is true or false

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Colchicine is a drug that:a

arrests cells in mitotic telophase. b. stimulates meiosis. c. prevents DNA replication. d. arrests cells in mitotic metaphase. e. prevents cells from entering prophase.

Biology & Microbiology