It makes the bronze stronger and harder than either of the other two medals
The independent variable is the one you change, and the dependent variable is the one that changes because the independent changed (i think). The constant variable is the thing you can't change so the experiment is fair.
Independant: whatever causes the flowers to change color
Dependent: the flowers change color
Constant: same soil type, same conditions, etc.
A straight chain hydrocarbon with the formula C5 H10: has a double C-C bond
Answer:

Explanation:
Expanded Structure shows all the atoms and the bonds of the molecule. It is important to remember, each Carbon molecule have four bonds, while the Hydrogen just one. So:
1)
Pentene. 5 Carbon molecules, 10 Hydrogen molecules. It's an isomer, so this organic compound has multiple arrangements.
2) 
Ethane. 2 Carbon and 6 Hydrogen Molecules. Check it below.