Skip to content
Prep
Freely
Home
TOEFL
IELTS
Guides
Log in
Sign up
P
Account
Profile
My progress
Settings
Log out
TOEFL
/
Listening practice
/ Section X8WK
Listen to an Academic Talk
Listen to part of a talk in a biology class.
Listen
31. What did researchers discover in 2022?
A
Glass frogs have no red blood cells.
B
Sleeping glass frogs store most of their red blood cells in the liver.
C
Glass frogs change color when they wake up.
D
Glass frogs sleep only during the day.