Air is 23% oxygen by mass. What mass of air would be required in order to obtain 500 kilograms of oxygen?

Which of the following describes qualitative data? a) recording the temperature of a solid as it is warmed. b) noting the color of a solution as it is heated. c) measuring the volume of an object by water displacement. d) taking the mass of an object using a balance.

Organisms are classified as producer or consumers according to the way they ?

My plate recommends that of your nutritional intake comes from fruits and vegetables. a. 30% b. 50% c. 20% d. 40%