Which of the following types of species interaction is incorrectly paired to its effects on the density of the two interacting populations? a) predation-one increases, one decreases b) parasitism-one increases, one decreases c) commensalism-both increase d) mutualism-both increase e) competition-both decrease

4. multiple crosses were made between true-breeding lines of black and yellow labrador retrievers. all the f1 progeny were black. when these progeny were intercrossed, they produced an f2 consisting of 91 black, 39 yellow and 30 chocolate. a. propose an explanation for the inheritance of coat color in labradors. b. propose a biochemical pathway for coat color determination and indicate how the relevant genes control coat coloration.