Mrs. Johnston heated 5 grams of sugar. The sugar first looked shiny, and then it melted and became dark brown. Finally, all that was left was a black, shiny residue. She then heated 5 grams of sand in the same way. The sand’s appearance did not change. What explains these results? a Sand is an element, but sugar is a compound.
b Heating the sugar caused a chemical change.
c Heating the sand caused a chemical change.
dHeat only caused physical changes in both the sand and sugar.

B

Explanation:

Heating the sugar causes it to burn, thereby inciting a chemical change in the glucose molecules.

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."