Answer: reproduction is reproducing
Explanation:lol
This is because it has many parts, arteries, and tubes that pass blood around the body. It is hard because it has many parts which are difficult to be cut open. Hope I helped!
A Vitamin K shot is given to infants soon after birth to reduce the risk of blood loss through hemorrhage.
Variation: people in the population need to have different traits.
Heritability: the different traits need to be able to pass from parent to offspring.
Differential Mortality: people need to have the probability of survival that is a function of the trait in question.
