As the Back East 2000 notebook states, &quot;Finding food and water, escaping hostile environmental conditions and predators, and securing a safe place in which to raise their young are primary factors that create the drive to migrate.
(primary factors; create; the drive to migrate) (their young; are; primary factors that create the drive; T:As the Back East 2000 notebook states, &quot;Finding food and water, escaping hostile environmental conditions and predators, and securing a safe place)
primary factors their young
create are
the drive to migrate
primary factors that create the drive T:As the Back East 2000 notebook states, &quot;Finding food and water, escaping hostile environmental conditions and predators, and securing a safe place