Imagine that doctors are observing a new disease, and they don't know what causes it. what are some possible causes of diseases? what kinds of things would scientists do to learn more about a disease and its cause or causes?

Directions: read the descriptions of the four islands presented in the lesson. 1. list two new traits that each new species of rat might demonstrate as it adapts to the conditions on each island. 2. introduce one of the four new rat species to another island and describe one challenge it would encounter and one success as it adapts to its new environment.

Which member of the following food chain will be least affected by ddt, a pesticide water pollutant, if bio-magnification is occurring? algae> zooplankton> crayfish> leopard frog> large mouth bass

Look at the photo of the leaf, which term best describes this leaf ? a-simple.b-parallel.c-lobed.d-tooth.