Answer:
All these are emerging infectious diseases.
Explanation:
The emerging infectious diseases refer to the infections, which have appeared freshly within a population or those whose occurrence or geographic range is enhancing briskly or is threatening to upsurge in the coming time. The emerging infections can be a result of:
1. Known agents, which have dispersed to novel geographic locations or new populations.
2. Previously unknown or undetermined infectious agents.
3. Previously known agents whose function in particular diseases was not determined previously.
According to WHO, infectious diseases are emerging at a rate, which has not been noticed before. Since the 1970s, many infectious diseases have been discovered like Ebola, SARS, avian influenza, mad cow disease, and West Nile encephalitis.
With the individuals traveling much more to far greater distances in comparison to the past, encountering with wild animals, and living in more densely populated regions has caused the emerging infectious diseases to spread briskly and is resulting in global epidemics, which is a major worry.
Ecological succession is a process of inhabiting a zoological area by a group of organisms. it involves many stages to reach the climax stage such as primary, secondary, tertiary names basing on the habitat where it occurs. once the organisms reach the most stable stage of the succession. thus it maintains equilibrium
Succession helps restore the equilibrium of an ecosystem by forming up new species, diversifying species, and basically by replacing the damaged, deranged, or disturbed community. For instance, when a sudden climate change occurred in a community, such as drought, dryness, fire, or heat waves, all living things that depends on water or survives in a cool, wet environment will die or migrate somewhere else. Thus, leaving that community vacant and/or unoccupied by any living things. Succession, then, will take place in that area by going through various stages until reaching the climax stage, in which the ecosystem is complete again. c: hope i helped :D