As a Low-Mass Main-Sequence Star Runs Out of Fuel in Its

question 11

Multiple Choice

As a low-mass main-sequence star runs out of fuel in its core, it grows more luminous. How is this possible?

• A) It explodes.
• B) It begins to fuse helium in the core.
• C) The core expands as it runs out of fuel.
• D) The core shrinks, bringing more hydrogen fuel into the burning region.
• E) Convection takes place throughout the interior, bringing more fuel to the core.

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Definitions:

Isotonic Solution

Solution that is equal in solute concentration to that of the cytoplasm of a cell; causes cell to neither lose nor gain water by osmosis.

Solute Concentration

A measure of the amount of a solute that is dissolved in a solvent, determining the solute's proportion in a solution.

Selectively Permeable Membrane

A membrane that only allows specific molecules or ions to pass through it by active or passive transport.

Osmosis

The movement of water molecules through a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration.