Explanation:
HIV attacks a specific type of immune system cell in the body. It's known as the CD4 helper cell or T cell. When HIV destroys this cell, it becomes harder for the body to fight off other infections. When HIV is left untreated, even a minor infection such as a cold can be much more severe.
The main function of white blood cells is to help protect the human body from infection as well as other foreign materials. White blood cells are also known as leukocytes, and they develop in bone marrow from stem cells. There are five different types of white blood cells<span>, including neutrophils, lymphocytes, monocytes, eosinophils and basophils.</span>
Answer:
Polygenic traits
Explanation:
Polygenic traits are traits that are controlled by more than one gene and the physical expression of these genes is significantly influenced by environmental conditions .Characteristics that show continuous variations are controlled by many genes.The genes that control them may be located near each other or even on separate chromosomes. They are often represented as a range of continuous variation because they are not discrete.
It would be Carbon Dioxide.