They observe it, run tests on many different things, and do expirments
Answer:
Photosynthesis is the process in which light energy is converted to chemical energy in the form of sugars. In a process driven by light energy, glucose molecules (or other sugars) are constructed from water and carbon dioxide, and oxygen is released as a byproduct.
The heart of a lazy person pumps blood less efficiently than an athlete who has trained and prepared to achieve a high performance, this can be understood with the example of football players who will play in other countries that have a higher altitude than the country of origin and has to go before to get used to the rarer air
Well theory isnt proven. It means you have a strong idea about the subject your talking about. So if a scientist finds evidence that suggests something against the theory then it can be changed.
