Final answer:
The declining sex ratio in the First Nation Community can be attributed to migration of males to urban areas, gender discrimination, and lack of access to healthcare facilities and inadequate education opportunities for females.
Step-by-step explanation:
The declining sex ratio in the First Nation Community can be attributed to several factors. One reason is the migration of males to urban areas, which leads to a higher proportion of females in the community. Additionally, gender discrimination may play a role, as it can result in a preference for male children and lead to a skewed sex ratio. Another factor could be the lack of access to healthcare facilities and inadequate education opportunities for females, which may contribute to lower survival rates for female infants and early deaths among women.