Answer:
There are two types of melanin--eumelanin and pheomelanin. In general, the more eumelanin in your skin, the darker your skin will be. People who make more pheomelanin than eumelanin tend to have lighter skin with freckles. Like many other traits, the amount and kind of pigment in your skin is controlled by genes
Explanation:
Answer:
through the process of respiration
Explanation:
Answer: More than 99 percent of all organisms that have ever lived on Earth are extinct. As new species evolve to fit ever changing ecological niches, older species fade away. But the rate of extinction is far from constant. At least a handful of times in the last 500 million years, 75 to more than 90 percent of all species on Earth have disappeared in a geological blink of an eye in catastrophes we call mass extinctions.
Though mass extinctions are deadly events, they open up the planet for new forms of life to emerge. The most studied mass extinction, which marked the boundary between the Cretaceous and Paleogene periods about 66 million years ago, killed off the nonavian dinosaurs and made room for mammals and birds to rapidly diversify
Answer:
b. Infection with a hepatitis virus
Explanation:
The infection with hepatitis virus can cause sever tissue damage that leads to permanent scarring.
The main function of xylem tissue in the plant transport system is to transport water.
Answer: C) or the third option.
