What two structures generate the cells responsible for immune responses? (A) B lymphocytes and T lymphocytes
(B) thymus and lymphocytes
(C) bone marrow and lymphocytes
(D) bone marrow and thymus

When the grand canyon formed many small mammal population were divided. some members of the population were on one side and others are on the other, therefore, they were no able to mate with one another. over time this separation and inability to mate with one another led to the emergence of new species. this type of speciation is called a) sympatric speciation. b) allopatric speciation. c) parapetric speciation. d) peripatric speciation.