Which of these is not a commonly mined metallic substance?
A.)Iron
B.)Lead
C.)Quartz
D.)Mercury

Neils bohr believed that electrons orbited the nucleus in different energy levels, based on strong support from

Scientific evidence tells us that the cause of earths four season is the tilt of earth as it revolves around the sun. the student is instructed to illustrate this information in a science notebook. how will the student illiterate winter in the northern hemisphere?

Why is the bottom layer of a trophic pyrimid the