Answer:
A. by reacting animal fat or vegetable oil with water.
D. by treating animal fat or vegetable oil with hydrogen
Explanation:
Water is insoluble in animal fat or vegetable oil so it makes a layer on the surface of oil. When animal fat or vegetable oil react with hydrogen, it produces solid oil called ghee not biofuels. Biofuel is produced when animal fat or vegetable oil react with alcohol.
First, it is necessary that this scientist decide on what point of the Cretaceous period he wants to study. Among several points he may want to study the evolution of microorganisms of that time, the life of a dinosaur species, or the evolution of dinosaurs, the flora that was established during this period, among others. This is the phase of the scientific method called Observation.
After that, he must enter the phase called "Elaboration of hypotheses" where he will raise questions about the point he decided to study. "How many flower species existed in that period?", "How many of these flowers can we observe today?" among others.
After that, he will enter the phase called "Experimentation", where he will establish a type of experiment and all the experimental factors and variables that will allow the hypotheses to be answered.
After the experiment he will collect the data that will be analyzed and that will give results that will answer the hypotheses previously established. This is the phase called "Analysis of the results".
At that moment, he will be able to reach the last phase of the scientific method, the phase called "conclusion", where he will show the conclusions that the experiment allowed to be established.
This makes sense because all scavengers eat, but not all eaters scavenge for food.<span />
