Depending on the organism, the cell can get its energy from the sun (Plant; Photosynthesis) or through ATP energy (Animal).
Struggled with this earlier but because of the high altitude only some animals can live there and thrive because of the lower oxygen levels
Hydrogen bonds are weaker than covalent bonds.
This might represent evolution of a species or the influence of the environment on the expression of a genotype.
B. Because a physical reaction is a change that can be seen. This particular situation is happening over a period of time, it isn’t something that happens instantly. Also I it would have been a chemical reaction, it would have mentioned something about the state of an element or the temperature or something along those lines.
