Option D – amphibians may use their skin for gas exchange is the characteristic feature of amphibians that differs from reptiles.
Explanation:
The amphibian skin is moist, thin and marbled and supplied by blood vessels running on its surface. The moisture present in the skin dissolves the oxygen present in its surrounding which is absorbed by the blood vessels. Special glands help the amphibians to keep the skin moist.
The very thick and tough scales present on the reptiles prevent them to absorb oxygen through their skin. Hence, they breathe and respire through their lungs.
Amphibians have three-chambered heart. They do not develop amniotic eggs. Adult amphibians although spend much time on land, they breed only in water due to the absence of amniotic sac
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Answer:
Explanation: The basic unit of a DNA is a Nucleotide. The nucleotide comprises of: the nitrogenous bases, a deoxyribose sugar and a phosphate group. The nitrogenous bases are the purines and pyrimidines . The include, Adenine, guanine, Thymine and cytosine
The correct answer from the choices listed above is option A. Adaptations took advantage of the presence of free oxygen in the oceans and atmosphere by the <span>evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules.</span>
Answer: The most reason was that cell-to-cell communication and the different chemical compositions of the cell walls of plant, fungi, and bacteria restricts the intercellular communication to their own species.
Explanation:
