Beginner in need of help (due to not knowing what the problem is called)

Support Basics & Interface
1

I have just started using blender as a means of getting a school assessment done as it is animation based. So what I have decided to make is an elephant. But I have a problem with not being able to see well as some parts are dark and I dont know what to do. Here are some examples

https://imgur.com/hlJhLS1

But I had a different file that was different and not this problem and i dont know how or why it happened
https://imgur.com/3uXbsJq

So if any one can help me that would be so appreciated. Thanks

2

Looks like you have inverted face normals.
Remove any doubles first (select all vertices and W / remove Doubles)
Then select all faces and recalculate normals (Ctrl+N). You can flip the normals of selected faces with W / Flip Normals

You can turn on the display of normals in the properties panel (shortcut N)

3

Thank you so much!

4

If you turn on backface culling (also in the N-panel) it helps u recognize the flipped normals while modeling.