2. __ Evolution is a change in the characteristics of a population from one generation to the next One mechanism of evolution is natural selection. Which of the following riatural selections condition examples can be classified as struggle to survive? A. A family of pigs has a mutation that makes them immune to flu. B. A family of dogs has a mutation that makes them immune to rabies. C. Male rams charge at each other's heads and fight to mate with a female. D. Many species of fish lay millions of eggs at one time, only a little of those survive.

## Step 1<br />The problem is asking us to identify which of the given examples can be classified as "struggle to survive" in the context of natural selection. Natural selection is a mechanism of evolution that involves the differential survival and reproduction of individuals due to differences in their traits.<br /><br />## Step 2<br />Let's analyze each option:<br /><br />### A. A family of pigs has a mutation that makes them immune to flu.<br />This is an example of a genetic mutation that provides a survival advantage, but it doesn't directly illustrate the struggle to survive.<br /><br />### B. A family of dogs has a mutation that makes them immune to rabies.<br />Similar to option A, this is an example of a genetic mutation that provides a survival advantage, but it doesn't directly illustrate the struggle to survive.<br /><br />### C. Male rams charge at each other's heads and fight to mate with a female.<br />This is an example of sexual selection, a type of natural selection where individuals with certain traits are more likely to find a mate. While it does involve a struggle, it's not the struggle to survive in the context of environmental pressures.<br /><br />### D. Many species of fish lay millions of eggs at one time, only a few of those survive.<br />This is a classic example of the struggle to survive. In this case, the struggle is for survival among the offspring, as only a small percentage will survive due to environmental pressures.