Charles Darwin and Alfred Russel Wallace both realised that within a population, there is for food and mates. What word completes the sentence?

True statement gravity force is more on bigger mass, less on smaller mass.all mass fall on planet with same acceleration and speeds

Mitochondria produce atp, a high energy compound. atp is used for all sorts of enzyme-mediated reactions, such as making proteins/nucleotides/etc, certain compounds cross the cell membrane, muscles move, etc.  without this source of energy, a cell will die. it will not be able to repair itself, defend against pathogens, etc.

When scientist examine data such as historical documents, they are using the "scientific methods"