Which of the following substances is a compound? O A. hydrogen gas
B. nitrogen gas
O c. table sugar
O D. oxygen gas

What is the name for the remnant of an asymptotic giant that has lost its shells? black dwarf white dwarf yellow giant black hole

What component of earth’s atmosphere exists entirely as a result of photosynthesis?

The three classes of rocks are sedimentary, metamorphic, and igneous. how are rocks classified into one of these three groups?