Can i claim my cousin and her 2 kids as dependents and get a refund for them since I provided for them all year and they have lived with me all year, their income is 0.

My cousin is 21, her kids are 3 yrs and a 4 month old. I've supported them all year and they have lived with me all year. Their income is $1000 for the whole year. Will I get a refund for the kids and a deduction for her?