You have it backwards.
Hitting the tree is collision.
Hitting the deer is other than collision.
A tree is a fixed object. When you hit a fixed object (tree,building, sign, pothole) it is a collision loss. Hitting other vehicles is also a collision loss. Think of it this way- you "collide" with something.
A deer is an animal. Other than collision (comprehensive) covers hitting animals (deer, dogs, skunk, bears etc). Most policies specifically list hitting an animal as an Other than Collision loss. Other than Collision covers those things that are not colliding with something. (fire, glass breakage, flood, theft).
The main difference: deer jump.....trees don't.
So....what happens if a deer runs out -you swerve, hit the deer and then go off road and hit a tree? This usually gets handled under Other than Collision since you hit the deer.
EDIT: Since you are taking a test -- here's a couple of things that I see trip folks up when they are learning about auto and homeowners policies.
When you are dealing with auto and homeowners - 1 thing that trips people up is Medical Payments coverage.
This coverage have a very big difference in the auto and homeowners version.
Automobile Med Pay- pays for medical bills (not wages/pain/suffering) incurred as a result of an accident for occupants in your vehicle regardless of fault (here's the different party) - it WILL pay for named insureds and residents of your household, as well as people who do not live in your household.
So- you and your friend are in a car - get hit. You both get a claim for medical payments coverage up to the per person policy limit.
Homeowners Med Pay- pays for medical bills (not wages/pain/suffering) incurred as a result of injuries that happen on the residence premises (insured property) regardless of fault. However, it does NOT pay for people who live there. It only covers people who do not live in your household.
So - you and your friend are standing on the deck of your home and the rail gives way and you both fall. Since your friend does not live in your house hold -she will have a claim under Medical Payments (and probably liability coverage too). However, since you live in the insured house - you will not have a claim for Medical Payments coverage. You are S.O.L.
I've even had attorneys screw this one up- so I wanted to point it out to you. Its a major difference that will help you understand the coverages better.
Also - another question people mess up-- is determining what is covered under an auto policy. A lot of people think that personal property is covered when it's in the car. Not true. The auto policy specifically excludes personal property.
So- how do you tell whats covered under the auto policy and whats covered under the home owners? Here's a simple rule of thumb that applies most of the time. If you were to take the car and turn it upside down and shake it....if it falls out it is not covered by the auto policy.
So- the Cd's in your car--will fall out. That is not covered under the auto policy. The CD player that is installed in the dash - will not fall out - it's covered under the auto policy.
The cell phones that are mounted into the car - will not fall out. They are now a permanent fixture in the car. Auto policy may cover. Cell phone that is just plugged into the cigarette lighter - will fall out - it is not covered under the auto policy.
In order for personal property to be covered when it is damaged/stolen from a car - you have to file under your homeowners policy.
Learning all this stuff at one time can be really tough. Hope this helps to clear up some of the issues for you.
Good luck on your test.