The correct answer is the following.
1. I WANT you to come to the party. (indicative)
2. I know that you ARE right. (indicative)
3. they asked me to BELIEVE them. (subjunctive)
4. they can't let me DRIVE. (indicative)
5. he prefers me to LEAVE my hair long. (subjunctive).
The best way to understand the difference is the following. Verbs in the indicative mood make factual statements. It is such as a command, an order. On the other hand, verbs in the subjunctive mood use clauses such as "that or "if," trying to express a request or suggestion.
El niño cayó del segundo piso.
cayó is the conjugation of the irregular verb caer for the third person singular in the preterite tense. The preterite tense is one of two simple past tenses. It is used to describe actions that took place or were completed at a certain point in the past. So, this sentence means:
The boy fell from the second floor.