The need for natural resource should increase.
No, it is not a reasonable gamble for Karen to skip the influenza vaccine this year.
There are many factors which can increase a person's risk of developing the influenza virus and some of these factors are age, health condition, weakened immune system, pregnancy, or chronic illnesses.
Karen is older and her age could act as a risk factor for influenza. In addition, each year there are different strains of the virus since the virus is constantly changing and evolving. Given this, a person who got the vaccine last year is still in danger of not having the antibodies which can protect from this year's strain.
Karen should get the influenza vaccine this year as well.
The answer is invasive species.
<span>Invasive species are species that are not native to the specific ecosystem, but they are capable of spreading widely through the ecosystem. This way they can threaten native species of the ecosystem or cause environmental harm.
</span>
<span>After being introduced into the
Hawaiian Islands, the cane toads greatly affect local ecosystem. In the new area, they
have a few natural predators and are able to spread. If they spread beyond
the area they are introduced, they become invasive species which can
overgrow native biotopes and are a great threat to the local biodiversity.
This could lead to the extinction of some native species.</span>
