An atom can be ionized by ____ it.

An atom can be ionized by ____ it.
 
  a. removing electrons from
  b. adding an electron to
  c. removing a proton from
  d. Either removing electron from or and adding an electron to

Question 2

Precession of Earth's axis causes the date at which perihelion of Earth's orbit occurs to slowly change.
 
  a. True
  b. False
  Indicate whether the statement is true or false

Question 3

The number of ____ in the nucleus determines what element the nucleus is.
 
  a. protons
  b. electrons
  c. neutrons
  d. None of these determines the element.
  e. All of these determine the element.