Grapghic organizer of levels of organization for the human body system

Explanation:

There are 7 levels of organization in the human body: 1). subatomic particles, 2). atoms, 3). molecules, 4). organelles 5). cells 6). tissues, 7).organs, organ systems

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.