Question

which would be the best evidence that a cell is using active transport to move a substance across its cell membrane?
atp is being rapidly consumed near the cellular membrane.
substances are moving rapidly across the cell membrane.
substances are moving from high to low concentrations.
substances are moving through channels in the cell membrane.

Explanation:

• Active transport requires energy (ATP) to move substances against their concentration gradient. Rapid ATP consumption near the cell membrane indicates energy - using active transport.
• Substances moving rapidly (option B) could be due to passive transport like diffusion.
• Substances moving from high to low concentration (option C) is passive transport (e.g., diffusion, facilitated diffusion).
• Substances moving through channels (option D) is facilitated diffusion, a type of passive transport.

Answer:

A. ATP is being rapidly consumed near the cellular membrane.