Susana romero barcos es alta
Alta is a feminine descriptive adjective and means tall. In Spanish, you can recognize both feminine and masculine adjectives. Since this sentence is describing Susana who is a woman, you need to use the feminine form of the adjective alto (tall). Recall that descriptive adjectives are used to describe some quality of a noun like size, color, or shape of a person, an animal, a thing, or a place.
Romero Barcos es inteligente
Inteligente is an adjective whose meaning is intelligent. This is a characteristic of Romero Barcos. See the word es in this sentence that is being used in the previous sentence as well. So es is the conjugation of the verb ser for the third person singular. In this way, We use the verb ser to talk about permanent or lasting attributes. In this way, this verb stands for descriptions, occupations, characteristics, time, origin and relationships.
Los dos hermanos son jóvenes
jóvenes is an adjective whose meaning is young. This adjective is given in plural form and can be used both for feminine and masculine nouns. See the word son here, that is the conjugation of the verb ser for the third person singular (ellos) because Los dos hermanos can be replaced by the pronoun ellos.
