Ken enjoys bird watching. every summer, he sees many ruby-throated hummingbirds in his garden. however, during the winter, he never sees any ruby-throated hummingbirds. which of the following is a testable hypothesis that ken could make to explain the winter absence of the hummingbirds?
a.
where do ruby-throated hummingbirds go in the winter?
b.
do ruby-throated hummingbirds like cold weather?
c.
ruby-throated hummingbirds do not like being cold.
d.
ruby-throated hummingbirds hibernate during the winter.