The life cycle of a frog includes which stages?

The life cycle of a frog includes which stages?

• A. Egg stage; tadpole stage (with gills); juvenile stage
• B. Egg stage; larval stage (with gills); adult stage
• C. Egg stage; tadpole stage; adult stage
• D. Egg stage; tadpole stage (with gills); adult stage (with lungs)

Answer: (D)

Frogs undergo metamorphosis, moving from an egg laid in water to a larval stage called a tadpole, and finally to an air-breathing adult. The tadpole is aquatic, with gills, a tail, and no legs. Through metamorphosis, it develops legs, its tail shortens or is absorbed, and lungs form, producing the adult frog that breathes air. So the life cycle goes: egg stage → tadpole stage (with gills) → adult stage (with lungs). This sequence is what makes sense biologically, since the adult differs from the larva in structure and respiration.

Frogs undergo metamorphosis, moving from an egg laid in water to a larval stage called a tadpole, and finally to an air-breathing adult. The tadpole is aquatic, with gills, a tail, and no legs. Through metamorphosis, it develops legs, its tail shortens or is absorbed, and lungs form, producing the adult frog that breathes air. So the life cycle goes: egg stage → tadpole stage (with gills) → adult stage (with lungs). This sequence is what makes sense biologically, since the adult differs from the larva in structure and respiration.