What is the difference between son, sois and somos?

Is anyone able to ? i am so confused. this sheet is about irregular preterit verbs and direct object pronouns in spanish.

Choose one of the following locations: guayaquil, sucre, or la paz. then, write an e-mail of 7-10 sentences, in english, as if it's from a travel agent who is trying to persuade a family in the united states to visit the city you chose. in the e-mail describe the each of the following in at least two sentences each: location, culture, sites, food, and activities. your descriptions must be persuasive and different from the lessons.

Which of the following groups does not have a connection? a. el pollo, los huevos c. la carne, la pera b. el pescado, el atún d. la naranja, el jugo