A Landslide is a type of mass movement that occurs when a thin block of soil, rock, and debris separates from the underlying bedrock.
Actually, this thin block of soil and rocks were held by Tree's roots so it do not separated from the bedrock. Now days, more and more trees were cutted down for modern development, and more landslides happen because of this.
The best answer to the question presented above would be the first statement. Stalactites are chemical sedimentary rocks that form when the minerals in the cave are left behind by the water. They saturate and form into these stalactites.
The Great Lakes were formed during the last ice age.