Explanation believe the answer is A. Average.
Answer:
D: a heterogeneous mixture with components of varying sizes
Heterogeneous mixture is a combination of substances that doesn't have uniform composition and properties. Just by looking at the mixture you can differentiate the compounds because they are so different. Using a sieve, allows the components with different sizes to separate, while one is retained, the others can pass the holes in the sieve.
Explanation:
The correct option is C.
Helium gas will have the highest velocity at a given temperature because it has the lowest atomic mass of all the gases given. The atomic mass of gases affect their rate of movement. The lower the atomic mass, the faster the gas molecules moves and the higher the atomic mass, the slower the gas molecules move.