What characteristic do photosynthesis and combustion share? 1.They both start with chemical energy.

2.They both involve chemical change.

3.They both occur in living organisms.

4.They both are endothermic.

D. They both involve chemical change.

Both photosynthesis and combustion are chemical changes. In photosynthesis, green plants produce their food in the presence of sunlight using carbon dioxide and water.

Combustion refers to something being burnt. It usually applies to burning of fossil fuels.

These processes are both chemical changes because:

- they are not reversible processes

- new products are formed.

- mass is conserved

- they require considerable amount of energy.

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.

the answer is:  

line graphs show patterns in data with variables that change over time; whereas, circle graphs show data as parts out of a whole (such as out of 100%).