A marine biologist measured the amount of heat radiated from an aquarium over the course of an experiment. He concludes that the aquarium is an open system. Explain why this conclusion is invalid.
1) An open system does not exchange energy with its surroundings, and the scientist only measured the exchange of heat.
2) An open system does not exchange matter with its surroundings, and the scientist did not measure the movement of matter.
3) An open system exchanges both energy and matter with its surroundings, and the scientist did not measure the movement of matter.
4) An open system exchanges matter but not energy with its surroundings, and the scientist did not measure the movement of matter.

4) An open system exchanges matter but not with energy with its environment, and scientists do not measure the movement of matter. I think the one that suits me the best is that I have really thought

this protocol provides a detailed procedure for agarose-based ip to purify and enrich the protein of interest.

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.