Ethan is observing chemical and physical properties of a substance. he heats a substance and observes that the substance turns from a brown solid to a black powder. he refers to several chemistry journals that claim this represents a chemical reaction. from his observation and research, he concludes that the substance goes through a chemical change when heated. how can ethan best defend his conclusion?
a by demonstrating that the substance will eventually melt if the temperature continues to increase
b by verifying that the substance is now made up of different molecules than before it was heated
c by verifying that the substance is made up of only one type of element
d by demonstrating that the substance is less dense after it is heated

Ry was studying two populations of the same species of lizards. one population lived on an island and the other lived on the mainland. both populations were affected by a hurricane that hit the island and the mainland with equal force. a year later, henry was testing the gene frequency and saw a decrease in genetic variation in the island species, but not in the mainland species. which best describes a conclusion he might have reached? gene flow greatly affects small populations, but large populations can recover. genetic drift greatly affects small populations, but large populations can recover. gene flow greatly affects large populations, but small populations can recover. genetic drift greatly affects large populations, but small populations can recover.

Identify the examples in which sam interacts only with natural resources

Nh3 +02-no + h20 is unbalanced what is the balanced equation