<span>Pioneer species is the first species to populate an area</span>
I would say c would be the best.
<span>Herpesviridae is a large family of DNA viruses that cause diseases in animals, including humans.
When a person infected once, his immune system develops antidot against the virus, so he becomes immune for that virus for rest of his life. In other words, he can't be affected from that virus again
Hope this helps!</span>
If a zebra mussel is discovered in a lake in Pennsylvania, then the ecologist would be worried because it is an invasive species. The zebra mussel is native to Ukraine and Russia, but if it has been found in Pennsylvania, than it means that it has been introduced in this area. As an invasive species, the zebra mussel can be very dangerous for the native species in the lake. The invasive species usually are more competitive for food sources than the native species, manage to reproduce quicker, bring in diseases, and the native species tend to not have defense mechanisms for them. This leads to rapid decline or even extinction in the native species, while the invasive spreads out quickly and takes over, resulting in dramatic change in the whole ecosystem.
You didn't attach the problem. Without it, I can't help you. Sorry.
