Final answer:
The human body can survive approximately two weeks without food, equating to about 42 missed meals assuming three meals per day. While individual tolerance to starvation can vary, death is likely after a loss of 40% of body weight. Additionally, humans have critical time limits for survival without oxygen (minutes), water (days), and under extreme environmental conditions.
Step-by-step explanation:
The human body's ability to survive without essential resources varies for each need. If we compare the human body to a car's gas tank, we see that humans can typically live up to two weeks without food, assuming they have enough water and shelter. This period represents approximately 42 skipped meals, considering a standard diet of three meals per day.
When considering a fuel gauge for the body, it's suggested that one may feel the need to "refuel" at meal times, well before the resource is completely depleted. This sensation of hunger is the body's way of indicating it's time to replenish, even though in most cases, the body has not reached a critical level of energy depletion. A person's response to skipping meals can range from hunger and fatigue in the initial days, to more severe effects over several weeks such as organ failure and severe weight loss.
Starvation begins when an individual has lost about 30% of their normal body weight, and death is almost inevitable after a 40% loss. Comparatively, humans cannot survive without oxygen for more than a few minutes, without water for more than several days, and extreme conditions of heat, cold, and pressure can also swiftly become incompatible with life.