Hypothesis: The increased period of exposure to the infected or sick individual (or pathogen carried by the sick individual) increases the number of individuals getting the infection and falling sick.
Null hypothesis: The increased period of exposure to the infected or sick individual (or pathogen carried by the sick individual) does not increase the number of individuals getting the infection and falling sick.
The similarity between the sea star larva of modern times and some primitive vertebrae larvae suggests that they <span>share a common ancestor with sea stars.</span>
