Question

1. which of the following best defines the concept of homeostasis in biological systems? a) the process by which organisms increase their population size to adapt to environmental changes. b) the process by which organisms maintain stable internal conditions despite changes in their external environment. c) the process by which organisms undergo growth and development from a single cell to a complex multicellular organism. d) the process by which organisms produce energy from food and oxygen through cellular respiration. 2) what would happen on a hot day if your brain did not receive input that your body was starting to heat up? a) you would start to sweat b) you would start to overheat c) you would start to shiver d) you would not feel any effect at all 3) the graph shows how cortisol levels change during the day. cortisol increases the production of substance z through positive feedback. if no other feedback affects substance z, at which point would the level of substance z be the highest? circle the letter on the graph below. 4) complete the sentence below by circling the type of feedback described in the scenario below and provide an explanation supporting your choice. scenario: during childbirth the stretching of the cervix during labor causes the release of oxytocin, which stimulates further contractions. these contractions lead to more stretching and more oxytocin release, intensifying the contractions until the baby is delivered. this is an example of negative / positive feedback because

Explanation:

1. Homeostasis is the maintenance of stable internal conditions despite external changes. Option b correctly defines it.
2. Sweating is a cooling mechanism. Without the brain receiving heat - input, the body would not initiate sweating and would overheat.
3. In positive feedback, an increase in one factor leads to an increase in another. As cortisol increases Substance Z through positive feedback, Substance Z will be highest when cortisol is highest, which is at point B.
4. In positive feedback, the response amplifies the original stimulus. In child - birth, stretching of the cervix leads to more oxytocin release and more stretching, which is positive feedback.

Answer:

1. b) The process by which organisms maintain stable internal conditions despite changes in their external environment.
2. b) You would start to overheat
3. B
4. POSITIVE because the response (oxytocin release and contractions) amplifies the original stimulus (cervix stretching).