While there is no graph provided and I cannot find the graph online, I will base my answer through theory.
In theory, the most common blood type is O+, followed by A+, then B+, then AB+. Rh negative blood is deemed to be rare. While the most common blood type is O+, the same blood type is also called the "universal donor" as a type O+ blood has no antigens attached in red blood cells therefore the probability of adverse reactions (i.e. hemolytic reactions) when transfused to other blood types are close to nil. In an emergency situation, wherein there is not enough time to do proper crossmatching, blood type O+ can be used therefore supplies of blood type O+ are easily depleted.
Answer:
An earthquake
, a forest fire
, a hurricane and a volcanic eruption.
Explanation:
An earthquake
, a forest fire
, a hurricane and a volcanic eruption are the events that is responsible for the suitable conditions for primary succession because all the population of animals and vegetation are removed from an area and the new type of organisms is start to living in that new environment. These new organism has the ability to survive that environmental conditions. These events completely removed the population in the environment and provides conditions for primary succession.