The information source for the inheritance of features is the DNA (Deoxyribo Nucleic Acid) molecules located in the chromosomes of the cell nucleus.

Organisms look similar because their body designs are similar, and these designs are based on similar blueprints.

We usually determine that two different individual organisms belong to the same species based on their similarity in appearance. Reproducing organisms create new individuals that share similarities with themselves, aiding in the classification of organisms into the same species.

Large numbers of organisms belonging to a single species increase their visibility. The abundance of reproducing individuals of a species draws attention and facilitates the study and understanding of that particular species.

Individual organisms engage in reproduction to create more individuals of their species. While it requires energy, reproduction is essential for the continuation of the species and the passing on of genetic information.