Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in heritable traits of a population over time. The term "natural selection" was popularised by Charles Darwin who compared it with artificial selection, now more commonly referred to as selective breeding.
It is a scientific law
Explanation:
A scientific law states a constant relationship between two or more variables, each of which represents a property or measurement of specific systems. It is a constant and unchanging rule, usually expressed mathematically which allows to predict the unknown based on what is known with logical and real relationships.
A scientific theory is a set of concepts and rules (scientific laws) that express the relationships between observations of such concepts and generates a principle or set of principles to explain a phenomenon.
They are called this because it's our senses. Sensory Nerves take in and communicate information about heat, cold, pressure, pain, position, and much more. They also take in information for either the outside world, or from within the body itself.
The answer is prokaryotic cells and Eukaryotas.