Which of the following best describes the innate nonspecific immune system?
a targeted and highly specific response to a single pathogen or molecule
a generalized and nonspecific set of defenses against a class or group of pathogens
a set of barrier mechanisms that adapts to specific pathogens after repeated exposure
the production of antibody molecules against pathogens

The body of water found at number 4 on the map above is the

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.

The serengeti plains are part of the african savanna ecosystem and are home to a variety of different species of plants and animals. the serengeti plains experience a seven-month period of seasonal drought each year, during which the ecosystem receives only four inches of rain and the availability of some resources becomes very scarce. which type of limiting factors does the seasonal drought in the serengeti plains affect?