Lifelong study The only way to narrow down the possible causes, Helgen said, is to study the entire life cycle of the frogs -- from the time females lay eggs in breeding ponds in spring to metamorphosis, when tadpoles become frogs.
(tadpoles; become; frogs) (Helgen; said; is to study the entire life cycle of the frogs -- from the time) (Lifelong study The only way to narrow down the possible causes; is; to study the entire life cycle of the frogs -- from the time) (females; lay; eggs; in breeding ponds; T:the time)
tadpoles Helgen Lifelong study The only way to narrow down the possible causes females
become said is lay
frogs
is to study the entire life cycle of the frogs -- from the time
to study the entire life cycle of the frogs -- from the time
eggs in breeding ponds T:the time