Hint: There is currently no agreement on what constitutes life. Organisms are open systems that maintain homeostasis, are composed of cells, have a life cycle, undergo metabolism, can grow, adapt to their environment, respond to stimuli, reproduce, and evolve, according to one popular definition.
Life is a distinguishing feature that distinguishes physical entities that have biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased (they have died) or because such functions were never present and they are classified as inanimate. Plants, animals, fungi, protists, archaea, and bacteria are all forms of life.
Around 4 billion years ago, the first signs of life appeared. Direct evidence of life, on the other hand, came from fossils dating back 3.465 billion years. The fossils belonged to ancient unicellular organisms that resembled cyanobacteria today.
The oldest known fossils are approximately 3.5 billion years old, which is 14 times older than the oldest dinosaurs. However, the fossil record may go back even further. For example, in August 2016, scientists discovered what appear to be fossilized microbes dating back 3.7 billion years.
Since then, life has evolved into a diverse range of lifeforms, ranging from microscopic microbes to multicellular plants that can derive energy from the sun.
Thus, life first appeared around 4 billion years ago.
Note: Many attempts to define what "life" means in the past have failed due to outdated concepts such as odic force, hylomorphism, spontaneous generation, and vitalism, which have now been disproved by biological discoveries. Aristotle is widely regarded as the first person to classify organisms.