@Tasnim Mohammed

[[Well another question will rise saying that if we evolved from apes what made us evolve to human and some still are not humans? --Tasnim]]

Hominids are a branch off of one of the larger ape branches on the evolutionary bush, and we are a small branch coming off of the hominid branch as are Neanderthals. "Lucy" was a hominid as was Homo erectus. So, we are still classified as apes because we are a subset of the large collection of ape branches. The ape branch that we hominids branched off of survived so we have Chimpanzees and Bonobos. Some of the other ape branches not directly connected to hominids also survived. Thus, we have a collection of various living apes as well as humans.

Think of the evolutionary bush where apes represent a branch that diverges into many smaller and smaller branches as you move up. Hominids are a small branch in this complex, and we humans are a twig coming off of the hominid branch. Thus, we are still within the ape branching complex. We are technically still apes!
But all apes are not the same.

Environment plays a huge role in determining why species diverge. Rising mountains, new deserts, new rivers, often divide an ancestral species so that the divided groups no longer interbreed. Once that happens, evolution tends to take them off in different directions depending on the opportunities. Other factors, such as the type of predators, the amount of rain, the amount of light, the temperature, and dumb luck, all play a role in how animals and plants evolve. Remember, it was a chance hit by an asteroid that took out the dinosaurs. Otherwise, the world would still be ruled by dinosaurs. We would not be here. It is thought that some chance factors, such as an alternation between long droughts that reduced forests in favor of savannas, and rainy periods that favored forests, acted in Africa to encourage the evolution of the hominid line. Piecing together the puzzle millions of years later (and the pieces don't always rationally fit together since dumb luck may be involved at times) is an incredibly difficult job, and even today we aren't sure of the exact reasons and timelines for human evolution.