What factors, other than exercise, would increase the heartbeat rate?

Emotions and anxiety can raise your heart rate, Body Temperature: If you become too hot or too cold your body senses a thermal stress load, The terrain, Wind, Dehydration, Diminishing glycogen stores — your muscles primary fuel source.

Explanation:

the generally accepted parts of modern cell theory include: all known living things are made up of one or more cells. all living cells arise from pre-existing cells by division. the cell is the fundamental unit of structure and function in all living organisms.

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.