Question

Both Seagulls and wild geese are large birds. They're also similar in that both kinds of birds can fly over great distances. On the other hand, seagulls are scavengers, while wild geese aren't. Seagulls, for example, are often found around garbage dumps. Geese, however, feed on things like seeds and insects. Another important difference between the two kinds of birds is that geese fly on long annual migrations of well over 1,000 miles. Seagulls will migrate far inland to search for food. However, they don't follow seasonal patterns of migration like wild geese.
Clue words showing that contrasts are being made in this paragraph include

A. and and similar.
B. both and difference.
C. while and however.
D. also and hand.

Answer 1

The words showing contrast can be found here:
 
"On the other hand, seagulls are scavengers, while wild geese aren't. "

and here "while" is the word that shows the contrast


"Seagulls, for example, are often found around garbage dumps. Geese, however, feed on things like seeds and insects."
Here we have the word "however" to show the difference

So the correct answer is C: while and however!