Please help with explanations
Lyme disease is caused by a bacterium transmitted to humans by deer ticks. Generally deer ticks pick up the bacterium while in the larval stage from feeding on infected whitefooted mice. However, certain other species on which the larvae feed do not harbor the bacterium. Therefore, if the population of these other species were increased, the number of ticks acquiring the bacterium and hence the number of people contracting Lyme disease—would likely decline.
Which of the following it would be most useful to ascertain in evaluating the argument?
A. Whether populations of the other species on which deer tick larvae feed are found only in areas also inhabited by white footed mice.
B. Whether the size of the deer tick population is currently limited by the availability of animals for ticks ‘s larval stage to feed on
C. Whether the infected deer tick population could be controlled by increasing the number of animals that prey on white footed mice.
D.Whether deer ticks that were not infected as larvae can become infected as adults by feeding on deer on which infected deer ticks have fed.
E. Whether the other species on which deer tick larvae feed harbor any other bacteria that ticks transmits to humans.
- Tick larvae eat infected mice -> pick up bacterium.
- Tick larvae eat other food -> don’t pick up bacterium
- Based on 1 and 2, increase other food to reduce number of tick larvae picking up bacterium
What would help us evaluate this argument? What will help us decide whether 3 will work as expected? The correct answer should strengthen or weaken the link.
A: Doesn’t help us determine whether the tick larvae will feed on the other species. Hence this answer choice is incorrect
C: Number of other animals that eat mice is irrelevant to us. Our concern is whether increasing the population of other food which the tick larvae feed on will lead to a decrease in the number of ticks that get infected. Hence this answer choice is incorrect
D: We are concerned only about deer ticks picking up the bacterium when in larval stage. Hence this answer choice is incorrect
E: We aren’t concerned about other bacteria. Hence this answer choice is incorrect
Now let’s look at the correct answer choice B. “Whether the size of the deer tick population is currently limited by the availability of animals for ticks‘s larval stage to feed on”
B presents the possibility that the deer tick population is currently limited by the availability of food. If that’s the case, increasing the availability of other food will NOT cause the deer tick population to spread out. It will instead result in an exponential population growth, with more number of deer ticks feeding on disease causing mice. This answer choice weakens the link.
Hope this helps 🙂