Boundary separating two masses of air of different densities
Answer: Liquid
“A substance will take on the shape of an open container if it is a Liquid. Explanation: The major state of matter are solid, liquid and gas. Liquid usually have a definite volume.”
I think it might be D because all waves travel through a medium. I might be wrong though.
<span>The answer is the biotic and abiotic interactions. Biotic factors are the living component in the ecosystem. This is divided into three groups - producers, consumers, and the decomposers. While the abiotic factors are the non-living components. One interaction between the two are with the plants. Since plants use water, sunlight, and carbon dioxide to produce food.</span>
Nuclear fusion and heat (thermal) energy