The plus signs in the diagram above indicate the concentration of a particular pollutant that exists at each level of the food chain. What concept is being demonstrated by this diagram?
A) Bioaccumulation
B) 10% energy rule
C) Biomagnification
D) Food chain instability

i am going to guess that it is co2.

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.

oxygen +1 most likely

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]