Help me please:( i need to choose the correct verb.

3. No one in Europe (was, were) familiar with the taste of pumpkins,
blueberries, or maple syrup until explorers brought these foods
back from the Americas.
4. One American food that helped reduce the famine in Europe
(was, were) potatoes.
5. A field of potatoes (produce, produces) almost twice as much food
in about half as much growing time as the same field would if it
were planted with wheat.
6. News of tomatoes, sweet peppers, beans, and zucchini (was, were)
received warmly in Europe, and now these foods are the heart and
soul of southern Italian cooking,
7. At our school the Original American Chefs (is, are) a club that
prepares and serves such American Indian foods as baked sweet
potatoes and steamed corn pudding.

Read the passage first of all if someone says your dream is impossible, they’re wrong. you can’t prove that something is impossible-all you know is that[it] hasn’t been done yet. people said no one could scale mount everest but in 1953, sir edmund hilary and tenzing norway gazed down upon the world from it’s summit. people said that man could not fly, but in 1903, orville and wilbur wright made the first sustained powered flight in a heavier-than-air machine. people said, “okay, we admit that someone could climb mount everest, and we admit that man has learned to fly, but no one will ever, ever walk on the face of the moon.” if we can send three men a quarter of a million miles away and bring them home safely, is there any great task we cannot accomplish? which identifies the textual evidence that best supports the claim: the authors purpose is to persuade? a: the author shares historical information about the wright brothers. b: the author states that men have walked the moon. c: the author states that others who think your dreams are impossible are wrong. d: the author wants to know what tasks we cannot accomplish.