Final answer:
The prepositions in the sentence are "to" and "to."
Step-by-step explanation:
In the sentence "Lakshmi sends emails to all her friends now and then," the prepositions are "to" and "to." The preposition "to" shows the relationship between the verb "sends" and the noun "emails," indicating that the emails are being sent to someone. The preposition "to" also shows the relationship between the verb "sends" and the noun "friends," indicating that the emails are being sent to her friends.