Which type of transport requires energy input from the cell? A. active transport, B. facilitated diffusion, C. osmosis, D. simple diffusion.

Step 1: Define the Problem

Identify which type of transport requires energy input from the cell.

Step 2: Break Down the Problem

Examine each type of transport to determine if it requires energy:

• Active Transport
• Facilitated Diffusion
• Osmosis
• Simple Diffusion

Step 3: Apply Relevant Concepts

• Active Transport: Moves substances against their concentration gradient, requiring energy (usually ATP).
• Facilitated Diffusion: Moves substances down their concentration gradient with the help of transport proteins, no energy required.
• Osmosis: Diffusion of water across a semipermeable membrane, no energy required.
• Simple Diffusion: Movement of molecules from high to low concentration, no energy required.

Step 4: Analysis, Verify and Summarize

• Active Transport is the only process that requires energy because it moves substances against their concentration gradient.

Final Answer

A. Active Transport