The second most abundant element in the solar system is
A) silicon. B) helium. C) oxygen. D) hydrogen. E) carbon.
Question 2
How do we know the expansion of the universe is accelerating?
A) We're really not that sure the expansion is accelerating; it's all just a theory.
B) The rotation curves of galaxies indicate the universe is speeding up.
C) White dwarf supernova in distant galaxies are fainter than they would be if the expansion were not accelerating.
D) Redshifts of distant galaxies are increasing with time, so when we repeat the measurements, the redshifts are larger.
E) We see more of the universe every night, as the observable universe grows in size.
Tooth Numbering System
Paranasal sinuses are part of the upper respiratory system.
The acetic acid–acetate pair as a buffer system
Schematic of the Earth–Moon system (without a consistent scale)
Diseases and Disorders of the Respiratory System
Metals reacting with oxidized oxygen