Final answer:
The correct adaptations for surviving fasting are Elevated cortisol levels and Enhanced gluconeogenesis, which help in glucose production and protein breakdown during periods of low food intake.
Step-by-step explanation:
To prolong survival during fasting, the body goes through several adaptations, including the elevation of cortisol levels and enhanced gluconeogenesis. Increased insulin secretion (option A) is not an adaptation during fasting, as insulin is primarily released in response to elevated blood glucose levels, leading to the removal of glucose from the blood. Therefore, option A is incorrect because insulin secretion decreases during fasting to prevent further lowering of blood glucose levels. Option B is correct; during fasting, cortisol levels increase, as this hormone helps stimulate gluconeogenesis and the breakdown of proteins to amino acids that serve as precursors for glucose production. Enhanced gluconeogenesis (option C) is also correct, as it is a critical adaptation that allows the production of glucose from non-carbohydrate substrates, providing the body with necessary glucose when dietary intake is low. Reduced autophagy (option D) would not be beneficial for prolonged survival during fasting, as autophagy is a process that breaks down and recycles cellular components, which helps maintain cellular health and provides substrates for energy production during periods of nutrient scarcity. Therefore, the correct answers that represent adaptations for surviving fasting are Elevated cortisol levels (option B) and Enhanced gluconeogenesis (option C).