4 3 4 2 Set Two Passage II Due to advances in medical science human life expectancy is constantly increasing As greater numbers of people live longer lives researchers are becoming more familiar with complex signs of aging However while scientists understand the signs of aging the molecular causes of aging remain a mystery Three scientists propose models to explain the human aging process Scientist 1 Aging is caused by an accumulation of mutations that cause damage to the body or prevent it from being repaired This accumulation eventually causes death Because most mammals do not live long enough in nature to worry about this process having been killed by accident disease or predators the body possesses few resources for addressing these mutations What resources the body does possess are adapted to be most effective in youth ensuring the animal lives long enough to propagate its species Scientist 2 Aging is caused by genetic tradeoffs where a gene hat provides a competitive advantage early in life exacts negative effect later in life Evolution is a race in which he fastest strongest most fertile creatures outbreed their Ompetitors causing their species to dominate even if that Deed strength and fertility comes at the cost of a shorter Ee A gene that suppresses cancer might also suppress stem Ils thus providing better health early in life at the cost the ability to replenish worn out cells Modern genomic alysis has shown that most genes that cause aging are not tations but are actually common across the species ientist 3 Aging is caused by an accumulation of damage that entually reaches the point of critical non viability While mage can be healed the repaired cells are not always as ctional as the original cells As more and more cells lose ectiveness the ability of the body to repair is decreased ucing the effectiveness of repaired cells further leading downward spiral that results in death While some genes cause aging show direct linkages to trade offs in youth y genes that cause aging do not Similarly while these es have no discernable positive value and considerable ative value they are also common across the species demonstrating they are not random mutations unique to ndividual 6 Scientist I s model would be most weakened if which of the following observations were made F A child possesses as many mutation clearing re sources as an adult G An adult possesses fewer mutation clearing resourc es than a child H Age causing genes do not possess positive tradeoffs in youth J A child possesses the same ability to repair cells as an adult 7 The scientist who describes the accumulated damage hypothesis implies that the mutation hypothesis is weakened by which of the following observations A Genes that cause aging are common across species Genes that cause aging have no discernable positive B value C As the body ages its ability to repair is decreased D Repaired cells are sometimes not as effective as new cells 8 Scientist 3 s model would be most weakened by which of the following observations F Cells with lower healing capacity are found in all species G Genes are reproduced at a lower rate after cells repair damage H Aging cells reproduce damaged genes while young er cells do not J Repaired cells are found to be restored to full func tion after repairing damages 9 Scientist 2 s model would be best supported by which of the following observations A Young cells have fewer mutations than old cells B Old cells have fewer mutations than young cells C A gene that increases cancer risk late in life increas es fertility early in life R Damaged cells are not as capable of reproducing as 10 According to the genetic tradeoff hypothesis which of the following observations provides the strongest evidence that aging is not caused by mutations F Genes which have negative effects in older organ isms are common across the species G A cell has the fewest mutations when it is young H Some genes responsible for aging show no positive value in youth J A child has more ability to repair cells than an adult Godke C STOPL