Once a Threshold Is Reached

question 163

Multiple Choice

Once a threshold is reached,

• A) the number of sodium gates that open depends upon the strength of a stimulus.
• B) a graded local potential will be unable to spread to a trigger zone of the nerve membrane.
• C) the resting potential of a neuron is restored.
• D) the potassium channels in the input zone open.
• E) the opening of sodium gates and the accompanying flow of sodium ions is an example of positive feedback.

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Definitions:

Silurian Period

A geologic time period that occurred roughly 443.8 to 419.2 million years ago, characterized by significant biological diversity and the early development of terrestrial ecosystems.

Ediacaran Period

The last (most recent) period of the Proterozoic eon, from 635 million to 541 million years ago; named for early animal fossils found in the Ediacara Hills in South Australia.

Gymnosperms

A group of seed-producing plants that include conifers and cycads, characterized by having seeds that are not enclosed in an ovary (fruit).

Large Dinosaurs

Large dinosaurs were prehistoric reptiles, including species like the Tyrannosaurus rex and Brachiosaurus, known for their massive size and diversity during the Mesozoic era.