A plant cell contains a large membrane bound, sac-like structure that stores materials such as water, salts, proteins, and carbohydrates. When this sac-like structure is full it makes the cell rigid, which enables a plant to stand up straight. This sac-like structure is most likely what organelle? A. nucleus
B. vacuole
C. chloroplast
D. mitochondrion

C maybe i forgot haha but its my bday!!

The correct answer is c

It depends on the surface of the levels. the rougher the surface, the greater is the frictional force. for rougher surfaces, you would need to exert greater force to move the object. the concept is that, you must overcome the frictional force in order to bring the object into motion. this is the reason why we add lubricants to the joints so they could easily move. this answer was on