Because of its similarities . It is the process by which organisms are most suited to their local environment to survive.
Asteroids vary greatly in size and are mostly made up of frozen water and gas. This one is true.
They are said to be "mostly formed of ice and gas" as they rarely can be found consisting of stone, nickel and iron. These are extremely dangerous in our Universe.
Most models can't incorporate all the details of complex natural phenomena. For example, when measuring distances around the Earth it's convenient to model the Earth as a sphere, but this doesn't incorporate variations in distance because of mountain ranges, valleys and other topological features the traveler must traverse. Incorporating these additional details would make the model too complex for easy use. Since models must be simple enough that you can use them to make predictions, they often leave out some of the details.
ALSO.
The conformation of molecules are based on probability. It fails to take into account the electronegativity of individual atoms. And it is ineffective in showing inorganic interactions with metals and such.
Well maybe that species evolved over time to get faster and be more durable because of the need to run away from lions and other prey.
For mutations to affect an organism's descendants, they must: 1) occur in cells that produce the next generation, and 2) affect the hereditary material. Ultimately, the interplay between inherited mutations and environmental pressures generates diversity among species.