Cockroaches, also known as roaches, are insects that belong to the order Blattodea. They are one of the most primitive groups of insects, having existed for over 320 million years. There are over 4,000 species of cockroaches known to science, but only about 30 species are associated with human habitation.

Roaches are characterized by their flattened, oval-shaped bodies, long antennae, and six legs. They range in size from less than 1 cm to over 10 cm in length, and can be brown, black, or reddish in color. They have a tough exoskeleton that provides protection and support to their bodies.

Roaches are omnivorous and will eat almost anything, including food crumbs, plants, other insects, and even feces. They are nocturnal insects, and are often found in dark, damp, and warm environments such as kitchens, bathrooms, and basements.

The life cycle of a cockroach involves several stages, including egg, nymph, and adult. Female roaches lay eggs in a protective egg case called an ootheca, which can contain anywhere from 10 to 50 eggs. Nymphs emerge from the egg case and resemble miniature versions of adult roaches. They go through several molts as they grow, eventually reaching adulthood. The lifespan of a roach can range from a few months to over a year, depending on the species.

Roaches are considered pests because they carry diseases, can contaminate food and surfaces, and emit unpleasant odors. They are also difficult to control, as they are known for their ability to quickly adapt and evolve in response to changes in their environment.