Male amphibians, including frogs and toads, have been plague…

Male amphibians, including frogs and toads, have been plagued by feminization, deformity, behavioral abnormalities and sterility.  Biologists from the University of Florida investigated whether reproductive problems among populations of cane toads (Bufo marinus) are caused by poisons from chemicals associated with agriculture. The biologists collected local adult cane toads from more than 20 different locations. Toads were collected from areas close to agriculture, both large-scale and small-scale farms, as well as from suburbs that are nonagricultural areas. Based on this study, what is/are the test group(s)? 

Salmon live in both fresh water and salt water during their…

Salmon live in both fresh water and salt water during their lives. They are born in in fresh water but migrate out to marine waters for most of their life. Eventually, they return to the place they were born in fresh water to spawn. Changing between fresh water and salt water affects the balance of water in their body. Salmon have an internal control system called osmoregulation that restores the balance by negative feedback. This is an example of which characteristic of life?