Question

some molecules need to use energy from the cell to move across the membrane. this movement is called active transport. other molecules can cross the cell membrane without using cellular energy. this movement is called passive transport. select the true statements. some molecules cross the cell membrane without using cellular energy. molecules exit the cell by crossing the cell membrane. cells must maintain homeostasis. passive transport requires energy from the cell.

Explanation:

• The text clearly states that other molecules can cross the cell membrane without using cellular energy (passive transport), so "Some molecules cross the cell membrane without using cellular energy" is true.
• Molecules do exit the cell by crossing the cell membrane as per the context of transport mechanisms described, so "Molecules exit the cell by crossing the cell membrane" is true.
• While cells must maintain homeostasis (a fundamental cell property), there is no direct connection shown in the given text to support this statement from the provided transport - related description.
• Passive transport does not require energy from the cell (as per the definition in the text: "Other molecules can cross the cell membrane without using cellular energy. This movement is called passive transport"), so "Passive transport requires energy from the cell" is false.

Answer:

Some molecules cross the cell membrane without using cellular energy.
Molecules exit the cell by crossing the cell membrane.