Which of the following is not an example of a polymer? protein nylon kevlar concrete

the earths atmosphere is made up of nitrogen and oxygen. solids can turn into gasses through a process called sublimation. sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase.

hope this : d

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle