The frog is considered a better swimmer than the toad because it

Analyze the question: It asks why a frog swims better than a toad. We need to compare the two animals' body structures and find the feature most directly responsible for swimming ability.

Explain the concept: Frogs and toads are both amphibians (Class Amphibia, Order Anura), but they are adapted to different habitats:

• Frogs have smooth, moist skin and a slim body. They live near water and are strong swimmers. Their hind feet have well-developed webbing between the toes, which acts like a paddle.
• Toads have dry, warty skin and a stout body. They live mostly on land and have little or reduced webbing. They crawl or make short hops rather than swim.

Step-by-step evaluation of the options:

• A. Has more pronounced webbed digits. The web of skin between the toes increases the surface area pushing against the water. This gives more thrust per kick, and it is the main adaptation for swimming. This fits the question.
• B. Has much longer and stronger hind limbs. Frogs do have longer hind limbs than toads, and this helps with both leaping and swimming. However, the difference is mainly an adaptation for leaping, and "much longer and stronger" is an exaggeration. The feature that most directly distinguishes swimming is the webbing.
• C. Lives in water most of the time. This is a habitat statement, not a structural reason. Frogs live in or near water but also spend time on land, so it is not the best explanation.
• D. Is more streamlined than the toad. Frogs are somewhat slimmer, but this is a minor factor compared with webbing.

Exam tip: Remember "Frog = Fins (webbed feet); Toad = Terrestrial (dry, warty skin)". When a question asks about swimming, think of webbed feet. When it asks about leaping, think of long hind limbs.