cercariae

"My sister is a biologist studying the effects of pollution on local river ecosystems. "

"Not everyone will be infected when an epidemic strikes."

"a blood sample"

"From this vantage point we can observe the behavior of the animals in their natural habitat."

""The veterinarian found trematodes, or parasitic flatworms, in the sheep's liver." "

"The student had numerous assignments to complete before the weekend. "

"The guard blew his whistle to indicate imminent departure."

"It is generally known that the Earth is round."

"The children watched the butterfly larva, a tiny caterpillar, munch on a leaf in their classroom garden. "

"The parasitic capacitance in the circuit caused unexpected delays in the computer program's execution. "

"Even from a young age it was clear that she had the potential to become a great musician."

"The infection spread quickly through the classroom after one student got sick. "