I think the answer is NUCLEUS.
Hope it helps!
<span>It is process through which plants and other photoautotrophs generate carbohydrate and oxygen from carbon dioxide, water and light energy in chloroplast. It is two stage reaction-
1.Light dependent reaction- in this sunlight is absorbed by chlorophyll and converted into chemical energy and stored in the form of NADPH and ATP. It takes place in thylakoid membrane in chloroplast.
2.Light Independent Reaction- in this energized electrons from the light dependent reaction provides the energy to form carbohydrate from carbon dioxide molecules. It is known as Calvin cycle.</span>
The reason is because of the theory "the path of least resistance." The bird is not touching anything else, so it doesn't become our fried birdie dinner.
photosynthesis: needs light to happen
Cellular respiration: waste products are carbon dioxide and water.
Chirping, if that's what you mean.
