bananas and apples are his favorite (fruit)这里的fruit要加s吗，还有tomatoes and carrots are his

favorite (vegetable)要加s吗

要加的，因为表示种类的时候要用复数，而且句子中都是两种水果和蔬菜，是复数的，就更应该加S了。

要加S的, 泛指一类物质时可数名词要用复数形式。

that people eat in China and Europe, wherever, is exactly the same genetically as every other one. And just like human identical twins. Every banana is grown basically by taking a cutting from one and turning it into another tree. So every Cavendish banana that we eat. There are no seeds, that I eat, which are called Cavendish bananas, the bananas we eat;s most popular fruit by far — are very, very vulnerable to a lot of diseases. And the reason for this is that bananas, every banana you eat"Bananas are, for all their ubiquity — and it's the world', are fundamentally clones of each other