D. Genetic variation increases the likelihood of an allele being present that is best suited for the environment.
Light gates are more reliable. When using a manual stop watch, it is difficult to stop it at an exact time. A light gate is able to detect when an object passes through a 'gate' with the infrared transmitter and receiver.
Gamma rays, X-rays, most ultraviolet rays, and some infrared are absorbed by the atmosphere but do not reach the Earth's surface
Answer:
strontium has 50 neutrons
Can i get brainliest . i think it was used as a way of communication.