Somebody help me please

Invasive species are one of the major threats to biodiversity. these species multiply quickly and compete with native species for food, sunlight, spac and other resources. on the map, determine the area where native species will have limited resources available to them due to invasion threat from invasive species threat very low low medium high very high

The response is the basis for vaccination. primary secondary tertiary none of the above

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.