question:
The elements sulfur (S) and oxygen (O2) combine to form a substance called sulfur dioxide (SO2). Sulfur dioxide is also formed when coal and oil are burned. Sulfur dioxide can best be described as

answer:
a compound

question:
Which example describes a behavioral adaptation?

answer:
A bird builds its nest in the ash near a volcano.

question:
Young frogs do not resemble adult frogs. Which term is given to this pattern of development in frogs?

answer:
metamorphosis

question:
What is the smallest unit of an element that still has the properties of that element?

answer:

an atom