Is it multiple choice? I believe it's brain, but I could be wrong.
In the experiment, the independent variable is the drug amount. Experiment group is given certain amount of drug, control group is not given the drug. The dependent variable is the body fat. I think you means the control is the living environment including food and water.
Answer:
Q.1: I can't help you with this, sorry :(
Q.2: Seaweed is the producer because it takes energy from the water and sun in thermal reactions.
Q.3: Phytoplankton is the second-order consumer because they eat first-order consumers.
Q.4: Whelks and crabs because they eat limpets, which eat producers, and they also eat seaweed.
Q.5: Gulls are carnivores because they eat the crabs, and so are crabs because they eat mullets
Q.6: Limpets and lobster would become less populated, but not yet endangered. Gulls would starve and probably disappear from this ecosystem.
Q.7: Whelks' numbers would decrease because of the number of lobsters consuming them, but then lobsters would starve because of the decline in their food. Then this would repeat, shaking the whole ecosystem.
It would be the pubis bone.
Auroras normally occur in the Earth's thermosphere.
