Patients with brain tumors may elect to have a procedure known as gamma knife. in a typical gamma knife procedure gamma rays are directed toward a tumor with contact to surrounding tissues.
limiting contact between gamma rays and healthy tissue is important because
a) gamma rays are low frequency and may disturb mitochondria.
b) gamma rays are high energy and may cause damage to healthy cells.
c) gamma rays are have long wavelengths and may heat up healthy cells.
d) there is no risk associated with exposure of healthy cells to gamma rays.

B) gamma rays are high energy and may cause damage to healthy cells.

Explanation:

Gamma rays (γ) are a type of electromagnetic radiation formed by highly energetic and high frequency photons. They have a great penetrating capacity, being able to propagate thousands of meters in the air and pass through steel sheets up to 15 cm thick. They propagate in vacuum at the speed of light, about 300,000 km/s.

Gamma rays are high energy and in contact with the tissues of the human body can cause serious problems. Gamma rays passing through our body produce ionization in cellular tissues. High levels of gamma rays can produce dangerous tissue ionization and can cause damage to healthy cells.

answer: decrease

a limiting factor is the one which decrease the abundance, distribution and causes extinction of the population of species in a ecosystem. here, predators including hawks, owls and snakes are the limiting factor for the population of mexican free tailed bat.   although bats are nocturnal animals as they forge for food at night these predators also may remain active during night which can decrease the population of the mexican free-tailed bats. also, these bats eat only one type of insects that are moths. the food can also be a limiting factor as all 400 members are dependent upon same type of food needs that are moths. the decrease in the moth population can cause decrease in population size of the mexican free-tailed bats.

therefore, the scenarios will most likely to decrease the population size of the mexican free-tailed bats.