How is it possible that the gravitational pull of the moon affects the tides?

Question: How is it possible that the gravitational pull of the moon affects the tides?
- Keywords:
  gravitational pull,
  moon,
  tide
Asked by Gravity3984 to Deborah, Euan, Maheen, Rob, Stu on 19 Jun 2016.
- Euan Allen answered on 19 Jun 2016:
  
  The same way that the gravity of the sun pulls the Earth around it.
  
  As the moon goes around the Earth, the body of water nearest to the moon gets attracted up to it, which causes a high tide. When the moon passes the tide lowers and eventually reaches a minimum when the moon has moved around the Earth by 90 degrees.
  
  Take a look at this webpage which draws it for you:
  http://astro.unl.edu/classaction/animations/lunarcycles/tidesim.html

Question: How is it possible that the gravitational pull of the moon affects the tides?