3. Look at the sentence below. Why do we use the direct object pronoun lo to replace - helado- ice cream.

Yo compro el helado.

Yo ___lo___ compro.

There are two reasons. Think of feminine, masculine, singular, plural.
Chart: Direct Object Pronouns lo - it (m), los - them (m), la - it (f), las - them (f)

The reason why we use the direct object pronoun "lo" to replace "helado" in the sentence is because "helado" is a masculine singular noun, and "lo" is the masculine singular pronoun that replaces it. So, "Yo lo compro" means "I buy it" referring to the ice cream.