D Streak. The student is scratching it on white paper to test the streak.
Answer:
Explanation:
Each type of muscle tissue in the human body has a unique structure and a specific role. Skeletal muscle moves bones and other structures. Cardiac muscle contracts the heart to pump blood. The smooth muscle tissue that forms organs like the stomach and bladder changes shape to facilitate bodily functions.
I think the answer is A. forms many organic molecules :)
Answer:
b to a
Explanation:
since cells in membranes move from high to low concentration (diffusion). b has more molecules, so it will go into a.
