Earth's original atmosphere probably consisted mostly of which gas?
a. oxygen
b. nitrogen
c. water vapor
d. carbon dioxide

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit

Suppose that a certain fortunate person has a net worth of $71.0 billion ($7.10×1010). if her stock has a good year and gains $3.20 billion (3.20×109) in value, what is her new net worth?

The biomedical technique in which a part of the brain is destroyed with electric current is known as a. electroconvulsive therapy b. prefrontal lobotomy c. bilateral cingulotomy d. tardive dyskinesia