Carrying capacity is the property of ecosystem which indicates the number of individuals of population of species or group of species an ecosystem can sustain in terms of availability of resources (food, shelter). A population of herbivores is at it's carrying capacity for it's habitat. Immigration is the arrival of members of species to a new habitat for the purpose of deriving resources not found in their previous habitat or new habitat is more suitable then previous habitat. Immigration will increase the number of individuals in the ecosystem. Therefore, immigration will result in a sudden rise in a population that far exceeds the carrying capacity.
"an increase in predators" would likely lead to an increase in genetic variation in a population of squirrels, since the squirrels would have to adapt to the new threats.
Meningitis is the inflammation of the meninges covering the brain and spinal cord. One of the physical symptom is Kernig's sign. It is done by letting the person to lie flat and flexing the thigh and hip to 90 degrees. If the leg cannot be straighten then it means it is a neurologic positive sign for Meningitis.