Question

Funds are scarce,so---- are needed to build homes destroyed by the flood

Answer 1

Thank you for asking the question!
Funds are scarce so, volunteers or participants are needed to build homes destroyed by the flood. 
The nature of the sentence indicates that a specific sort of people are required who can help in restoring  the victims of flood back to their normal life and help rebuild the infrastructure of the area again. 
Hope it helps.