Tetrapods and Apes
"Why are humans two legged when most animals have more?"
Actually, I think you'll find that humans are better described as "4-limbed" rather than "two-legged"
Along with thousands of other animals that are thought to have evolved from a common 4-limbed ancestor. (I think the term is tetrapod in cladistics)
Cows, tigers, frogs, lizards, sparrows, gorillas, etc etc etc. All have 4 limbs.
Oh, and humans didn't evolve from apes - we ARE apes. Humans are genetically closer to Chimps than gorillas, and chimps are gorillas are both apes, so...