Here are the names of some substances: sulphur, copper, oxygen, iron, water, magnesium, mercury which substance: is at gas room temperature? is a liquid metal? is a solid non-metal? is a chemical compound?

Gas at room temperature: Oxygen

Liquid metal: Mercury

Solid non-metal: Sulphur, Copper

Chemical compound: Water

Explanation:

                    It is highly reactive non-metal and third most abundant element   in the universe after hydrogen and helium. Diatomic oxygen(O₂) constitutes 20.8% of earth atmosphere that used in respiration in living organisms.

                    It is shiny, silvery and only metal which is found in liquid state at normal room temperature. Most common use of mercury is in thermometer, barometer, sphygmomanometer etc.

                    It is bright yellow crystalline solid non-metal at room temperature in elemental form. Combined sulphur exists in sulphates and sulphides i.e. CaSO₄.2H₂o, MgSO₄.7H₂O, PbS, ZnS etc. Abundance in earth crust is only 0.03-0.1%.

                   It is pinkish-orange, malleable and ductile metal found in solid state at room temperature. It is commonly used in making wire, alloy etc.

                   Water covers 71% of earth surface. A molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. It is crucial for all forms of life.

muscle endurance

explanation:

i can do 50 in a row ( but i get so tired after that)

i think the answer is a, hope this is right, that would be my best guess.