When the Sun was younger, how did its habitable zone compare with its habitable zone today?

When the Sun was younger, how did its habitable zone compare with its habitable zone today?
 
  A) narrower and closer to the Sun
  B) narrower and farther from the Sun
  C) wider and closer to the Sun
  D) wider and farther from the Sun

Question 2

An electron and a proton are separated by a distance of 1 m. What happens to the size of the force on the proton if the electron is moved 0.5 m closer to the proton?
 
  A) It increases to 4 times its original value.
  B) It decreases to one-half its original value.
  C) It increases to 2 times its original value.
  D) It decreases to one-fourth its original value.
  E) It increases to 8 times its original value.

Question 3

Two cars collide head-on on a level friction-free road. The collision was completely inelastic and both cars quickly came to rest during the collision. What is true about the velocity of this system's center of mass?
 
  A) It was always zero.
  B) It was never zero.
  C) It was not initially zero, but ended up zero.

Question 4

Holly intends to swim to a point straight across a 100. m wide river that flows at 1.2 m/s. If she can swim 2.5 m/s in still water, at what angle must she swim upstream to achieve her goal?
 
  What will be an ideal response?