What is the difference between a muscular strength exercise and a muscular endurance exercise?

Muscular strength exercises build neuropathways to your brain, strengthening and building your muscle. Muscular endurance exercises work the muscle you already have. For example, weight lifting would be muscular strength because you're building muscle. Running would be muscular endurance because you're seeing how long those leg muscles can last. However, the two can also "intermix" and you usually do both at the same time.

oxygen and carbon dioxide

Explanation:

Small, uncharged substances such as oxygen and carbon dioxide can pass through the membrane by diffusion, down their concentration gradient.

Larger molecules or charged molecules cannot easily diffuse through the plasma membrane, and require the help of proteins to get into and out of the cell.

Organelles are relatively large molecules, and likely need a process called endocytosis to pass through the cell membrane into the cell, or exocytosis to pass through the membrane outside of the cell.

Endocytosis and exocytosis rely on membrane-bound vesicles to move substances across the membrane to their destination.