Answer:
The frogs circulatory and digestive systems are physically connected because the frog’s digestive system includes its liver and this has a hepatic portal system through which veins pass and come out and that is the circulatory system so they are connected.
I believe the correct word in the blank would be biological. I don't think anything else will fit in, especially when monomers of biological polymers are truly larger and more complex.
Answer:
contractile vacuole
Explanation:
contractile vacuole is used for balance of water,salt etc