Diffusion Fundamentals

Steps:

• Identify key properties of diffusion: passive movement of particles from high to low concentration.
• Evaluate statement 1: diffusion requires no energy input, aligning with passive transport.
• Evaluate statement 2: rate increases with concentration gradient, per Fick's first law.
• Evaluate statement 3: occurs in gases, liquids, and solids, as particles move randomly.

Why A is correct:

• All three statements match diffusion's definition as net movement down a gradient without energy.

Why the others are wrong:

• B omits 3, but diffusion occurs across states of matter.
• C omits 2, but gradient drives diffusion rate (Fick's law: J = -D * dc/dx).
• D omits 1, but diffusion is passive, not active transport.

Not enough information on exact statements, but A fits standard diffusion facts.

Final answer: A