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:
The immune system protects the host from pathogenic organisms (bacteria, viruses, fungi, parasites). To deal with this array of threats, the immune system has evolved to include a myriad of specialised cell types, communicating molecules and functional responses.
Explanation:
It is called Fluid Mosaic Model. It describes the structure of the plasma membrane as a mosaic component. The structures such as phospholipids, protein, carbohydrates and cholesterol gives the fluid like character of the plasma membrane.
I think its c. igneous rock
Answer:
The correct answer is D. zygote and finally develops into a fetus
Explanation:
Zygote is formed by the fusion of male gametes and female gametes. It is considered as the first stage of development of a baby. Zygote is a unicellular structure which develops into an embryo which is a multicellular structure.
Then this embryo develops and is called a fetus at the starting of the 11th week of pregnancy. A developed fetus is the final stage of prenatal development.
Therefore during successful prenatal development, a human baby begins as a zygote and finally develops into a fetus. So the correct answer is D.
