Frogs have webbed toes and strong legs which help in swimming in water. Their long, powerful legs facilitate jumping on land. In addition, variety of feet modifications may be seen for tree climbing or burrowing.
They have smooth moist skin to help in gas exchange. Lungs are present for respiration on land.
Frogs are ectotherms. During extreme environmental conditions they either hibernate (winter) or aestivate (summer).
Frogs have three eyelid membranes: one is transparent to protect the eyes underwater, and two vary from translucent to opaque.
Arboreal frogs have toe pads to help grip vertical surfaces. In many arboreal frogs, a small intercalary structure in each toe increases the surface area touching the substrate.
Frogs show external fertilization. Their offsprings develop through a process called metamorphosis. The eggs are laid in water which then hatch into tadpoles, i.e. the aquatic larvae. Tadpoles resemble fish and respire through gills. Over a period of time they change in form into the adult amphibian.