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.

If you answer this i"ll give you brainiest and all these points me if you do i love you 7. a doctor is at work taking care of sick patients. she spends a few minutes trying to figure out why a particular patient is sick. she taps the patient's knee to test his reflexes. while she is examining him, the patient coughs on her. a) describe the function of the skeletomuscular system in this situation. (3 points) b) describe the function of the circulatory and respiratory systems in this situation. (3 points) c) describe the function of the immune system in this situation. (3 points) d) describe the function of the nervous system in this situation. (3 points) e) describe one way that any two of the doctor's body systems worked together in this situation. (3 points)

Which statement about dna replication is true? a. eukaryotes only have one circular chromosome that unwinds at multiple locations. b. eukaryotes can only replicate one segment of a chromosome at a time. c. prokaryotes can only replicate their single circular chromosome in the nucleus. d. prokaryotes only have one origin of replication to initiate replication.

Of seawater increases with decrease in the temperature. therefore, the cold water sinks to the deeper layers at the bottom