Nepal has made important progress over the past few years to promote equality, but the country still has one of the highest rates of child marriage in the world. 41% of Nepalese girls are married before the age of 18. Poverty is both a cause and consequence of child marriage in Nepal. Girls from the wealthiest families marry 2 years later than those from the poorest, who are seen as an economic burden, and who drop out of school and earn little money.

The word "those" in paragraph refers to ________.