Malthus studied limited resources and the impact of limited resources on human populations. how did these ideas contribute to darwin's ideas?
a. limited resources in an environment forces more genetic changes in individuals, allowing the species to evolve more quickly.
b. limited resources in an environment means that the individuals of a species cooperate so that all individuals survive.
c. limited resources in an environment forces some individuals to survive without food.
d. limited resources in an environment means that not all individuals of a species will survive or reproduce at equal rates.

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.