Patients with indwelling catheters are susceptible to infections because a) injected solutions are contaminated. b) their immune systems are weakened. c) infections can be transmitted from other people. d) biofilms develop on catheters. e) bacteria cause infections.

Which statement describes how favorable traits in a population relate to natural selection? they are the only traits that ever exist in the population. they build in the population over time. they are rarely passed on to offspring. they are found only in a few individuals within the population.