Answer:
a
Explanation:
This is owing to some nebulae (more than one nebula) come from the gas and dust thrown out by the explosion of a dying star, such as a supernova
The scientific investigation is the systematic approach of the scientists to answer the questions about the world. It is applied almost all of the theories including the Theory of Natural Selection. Darwin's theory of evolution is a result of scientific investigation. In this theory, they investigate by observing the distribution of species.
The chemical reaction could be vary with the condition but the nuclear decay rate is constant, here the option A is the right option.
