Which of the following best predicts and justifies how the proportion of the Tibetan population with big blood vessels living in the mountains will change over the next 1,000 years (assuming conditions remain stable)?

Question 2 options:

I predict that the proportion of individuals with big blood vessels living in the mountains will decrease because there is a variation in blood vessel size and those with the smaller blood vessels can store more red blood cells than larger vessels, so more oxygen can be moved to the body cells. Therefore, they have a better chance of surviving and passing this trait on to their offspring.


I predict that the proportion of individuals with big blood vessels living in the mountains will stay the same because there is a variation in blood vessel size and that variation will remain in a population. The is what is so cool about humans, we are all so unique.


I predict that the proportion of individuals with big blood vessels living in the mountains will increase because there is a variation in blood vessel size and those with the bigger blood vessels can deliver more oxygen to the body cells and therefore have a better chance of surviving and passing this trait on to their offspring.


I predict that over 1,000 years, the proportion of individuals with big blood vessels living in the mountains will not change because a change can’t happen to an individual, an individual can only increase the amount of red blood cells it makes, not its blood vessels.