It is B. Because you cannot give internal fertilization/ live birth inside.
Magnesium Phosphate is the answer
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
.
I attached the image related to your concerned question.
In theory, the part of the brain that is responsible for the sleep wake cycle is the hypothalamus; specifically, the ventrolateral preoptic nucleus of the hypothalamus. In the image, the location of the hypothalamus is pointed by the green square.
white dwarf
Explanation:
A appears on the chart at the point of low luminosity but high surface temperatures. This indicated a White Dwarf
A red giant is highly luminous stars mainly because of its large size. However, its surface temperature is hot a high when compared to white dwarfs. White dwarf surface temperatures can reach billions of degrees kelvin while red giants reach up to 5000 K on their surface.
A white dwarf is the last sequence of a low-mass star cycle and follows the red giant phase.
