Which of the following steps in a star's life cycle takes the longest?
a.
fusion of carbon atoms
b.
formation of a protostar
c.
fusion of hydrogen atoms
d.
fusion of helium atoms

Which of the following statements is true about planck’s law

What is the ph of a 0.0010 m hno3? 1.0 3.0 4.0 5.0

Select the statement that describe chemical properties a. antacid tablets neutralize stomach acid b. helium is the lightest monatomic element c. water freezes at 0 celsius d. mercury is liquid at room temperature