Which of the following is not natural acquisition of immunity?
a. contact with a pathogen
b. antibodies passed on from mother to baby through breast milk
c. vaccination
d. antibodies passed on from mother to fetus through the placenta

Which sentence best expresses the differing opinions of these two book reviews?

Ascientist is investigating the effects of salinity on fish development. he places fertilized fish eggs in an aquarium that contains low salinity and observes their development. what factor would improve experimental design the most? place the fish eggs in the open ocean because that is the natural habitat include another aquarium that has normal salinity to compare to the low salinity aquarium include an aquarium that replaces salt with sugar to confirm that the effects are specific to salt grow algae with the fish eggs in order to provide adequate nutrients to the developing embryos

Which of these outcomes is a negative impact of postindustrial societies on the environment? a. nomadic ways b. overpopulation c. overgrazing d. resource renewal