Of the following, which one is an observational study?

1. asking people for their opinion on the taste of a new cereal
2. checking the effectiveness of a new headache medicine by giving one group the new medicine and one group acetaminophen
3. tracking the temperature in a city over a five year period
4. measuring the average strength of a batch of metal by stressing some sample pieces until they deform

List two new traits (structural or behavioral) that each new species of rat might demonstrate as it adapts to the conditions on two of the four islands. choose only two islands that are described in the lesson. record the island latter and the major habitat feature of the island. then list two new traits each rat subspecies might demonstrate in order to survive the habitat on that island. note: new traits should be unique to that island and be in response to that island’s habitat feature. i cannot remember islands that were names in the lesson so only answer if you have done the lesson (5.13 life science 7b) choose 2 of the islands and describe a structural and a behavioral trait for a rat on each island so 4 total answers, 2 different structurals and 2 different behaviorals, one for each rat for each island

Which best describes the digestive system of arthropods? a incomplete, two openings b complete, one opening c two-way, one opening d one-way, two openings

Elephants in the savanna regions of africa dig holes in dried up river beds to reach water lying just below the surface. these holes provide drinking water for other animals as well. so, without the elephants, many animals might otherwise die from lack of water during the dry season. the location in which the elephants live is an example of a/n and the role they play in creating water holes is an example of a a) ecosystem; habitat b) community; niche c) habitat; niche d) niche; habitat