The answer is all of the above
Basically, there is a presentation of types of food and the amount of those foods over 50 years in this graph. This means the graph is showing amounts of certain foods over the time period. I'm guessing that basing off of the the previous text you're just noting a change in the breaks of birds based off of the diet available to them at certain times. The adaptations and natural selection will explain the changes because due to certain limited and available foods the diet of the birds change.
The blue whale! It’s actually not only the biggest animal in water but also the biggest animal in the world! :)
Prokaryotic cells do not contain a nucleus or any other membrane-bound organelle. Eukaryotic cells contain membrane-bound organelles, including a nucleus. So I belive the answer is A :P Hope it helps