A star’s life expectancy depends on its mass. Generally, the more massive the star, the faster it burns up its fuel supply, and the shorter its life. The most massive stars can burn out and explode in a supernova after only a few million years of fusion. A star with a mass like the Sun, on the other hand, can continue fusing hydrogen for about 10 billion years. And if the star is very small, with a mass only a tenth that of the Sun, it can keep fusing hydrogen for up to a trillion years, longer than the current age of the universe.
Answer:
a) Teeth arose from the rough scales of ancestral sharks.
b) Skeletal developments leading to the amphibian movement onto land probably evolved from lobe-finned fishes.
d) The anterior gill arch formed the basis for the evolution of the vertebrate jaw.
Explanation:
The animals we know today have physical characteristics that are evolutionary adaptations of characteristics of their ancestors, which have undergone a series of evolutions and modifications over the years giving rise to new species that have resulted in the species we know today. This process of evolutions and adaptations also happened with the ancestral species of fish, which allowed that today, they had characteristics such as teeth and jaws. Many of these evolutions occurred even in different species, such as the evolution that allowed the amphibians to have a skeleton, which evolved from the spine fins of fish.
