Final answer:
Gravity is not a survival need for the human organism, whereas oxygen, appropriate body temperature, and atmospheric pressure are immediate necessities for survival.
Step-by-step explanation:
Which of the following is NOT a survival need for the human organism? The correct answer to this question is d. Gravity. Humans can survive without gravity, as demonstrated by astronauts living in space. However, humans cannot survive for long periods without oxygen, without which we cannot survive more than a few minutes. Appropriate body temperature is crucial for bodily functions and survival, and a specific atmospheric pressure is necessary to maintain gases in solution in the body and to facilitate respiration.
While gravity does affect the body and can cause long-term health issues if absent, it is not considered an immediate survival need like oxygen, appropriate body temperature, and atmospheric pressure.