How can you say that we are alive?

Not sure whether to approach question in the metaphysical sense or biologically, so I searched for a definition on Wikipedia and was quiet surprised how it encompassed many of my thoughts:

Life is a characteristic distinguishing physical entities having biological processes (such as signaling and self-sustaining processes) from those that do not, either because such functions have ceased (death), or because they lack such functions and are classified as inanimate. Living things are composed of one or more cells, undergo metabolism, maintain homeostasis, can grow, respond to stimuli, reproduce (either sexually or asexually) and, through evolution, adapt to their environment in successive generations.

That's why we can confidently say that we're alive. Rocks, for instance, obviously don't have these regulating processes that living things do.

Thank you for that wonderful answer. I just want a clear answer that does life itself really exist even without the concept of life being made.

I would assume so, bacteria are alive yet they don't have the ability to think. In fact, we're the only animals capable of thinking that way.

That's the thing. We can just say that we are alive because we had the ability to think that we are and that bacteria are too. If bacteria do not even know that they are alive, then people just made the concept out of it to describe ourselves living things.

Arguably, every definition found in the dictionary is a human construct. "Living things are composed of one or more cells, undergo metabolism, maintain homeostasis, can grow, respond to stimuli, reproduce (either sexually or asexually) and, through evolution, adapt to their environment in successive generations." Collectively, these observations / characteristics define every extant and extinct species.

Just because we are human doesn't mean we are not animals.

We live just as other animals do.

We are animals. No one argued against that.

Yes, there is a basis to explain how something is alive; but isn't life a man-made concept that can still be mistaken or misunderstood just like an optical illusion?

Example...

The understanding of life itself as we see how it works.

There isn't absolute answer for this question, so we can't say anything.

My point is that we won't even know that we are alive if it wasn't taught to us.