Why does this recent discovery about the Galapagos finches prove that it's often challenging for scientists to determine when two groups of individuals are separate species? What factors do scientists need to consider when determining
whether a species is a new species or part of an existing species?

Cancer cells spread to other parts of the body by entering the bloodstream. which of the following organs could prevent a cancer cell in the bloodstream from spreading, and why? a. the spleen, because it releases lymphocytes into the blood b. the peyer's patches, because they release lymphocytes into the blood c. the lymph nodes, because they release lymph into the blood d. the thymus, because it releases lymph into the blood