In the lab on Trophic Interactions you were looking at behavior of mosquito larvae. The question being asked was: Does prey behavior change in the presence of a predator? What would be an appropriate null hypothesis for this experiment? Recall in Treatments 2 and 3, a predator was added to the mosquito tanks.

Null hypothesis: the behavior of mosquito larvae doesn't change in the presence/absence of predators added to the tanks in Treatments 2 and 3.

Explanation:

In statistics, the null hypothesis states that there are no differences between the two variables tested in the experiment, while the alternative hypothesis uses the experimental data in order to reject the null hypothesis. In this case, the alternative hypothesis will use the data from treatments 2 and 3 to confirm that predators can modify the behavior of mosquito larvae.

relative dating involves things like higher layers are most recent than rocks lower in the sequence. this can be extended to the known sequence of fossils. rocks containing rabbit fossils are later than those containing dinosaur fossils.  

absolute dating methods mainly use radioactive elements that have known rates of decay and produce recognizable products. for example potassium 40 decays to produce argon. once a rock has solidified the argon is trapped. by measuring the argon and potassium0 you can get an accurate number for the age.  

some other methods are good for archaeological ages. dendrochronology involves recognizing the sequence of tree rings. the orientation of magnetized particles in baked clay can be used to date a fire.

hope this .. .