Answer:
D: Carbon
Explanation:
The periodic table lists all the known elements. When looking at it, the only choice you will find is carbon. Therefore, carbon is the element.
Carbon is also by itself, just C.
Water is H2O, which is a molecule due to the 2 different elements.
Carbon Dioxide is CO2, which is a molecule due to the 2 different elements.
Air is just a mixture of different gas molecules, so therefore it is not an element.
Answer:

Explanation:
» The prediction is 98% correct because single displacement reaction type is highly possible.
This is because Fluorine has is more electronegative than Chlorine in Potassium Chloride. So, it strongly displaces Chlorine from the solution hence forming Chlorine gas.
» The 2% of wrong prediction maybe because of wrong reactant measurements following mole concept chemistry.
If you are asked the observation,
Observation » <u> </u><u>A</u><u> </u><u>green</u><u> </u><u>yellowish</u><u> </u><u>gas</u><u> </u><u>is</u><u> </u><u>formed</u><u>.</u>
This gas is Chlorine gas (Cl2)
Object one is 5.2 g/cm3
object two is 3.46g/ml
Im pretty sure its A funding because thats alot of money