Frogs have internal and external structures to help them survive, grow, and reproduce. Name an internal and an external structure, an tell how these structures of the frog survive.

Frogs have some important internal and external structures  that helps them to survive, grow and reproduce. Frog have almost similar internal anatomy to humans.

Frogs have the ability to respire through both lungs and skin. Skin is the external structure that helps them to respire in aquatic ecology.The skins helps to dissolves oxygen from the air and water and releases carbon-dioxide. Skin helps frogs to respire under water but if water do not have enough oxygen, frogs will drown.

An internal structure called liver is present in frog same as human beings. The liver releases chemical called bile that are utilized in digestion of fat and then emptied into the small intestine.

Hence, skin and liver are important for the survival of frog.

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme

i believe the correct answer is d