The antibodies to the HIV virus may take up to three months to appear in the blood of the infected person. Therefore, the second blood test is necessary three months after a person thinks that he/she has been exposed to HIV to check the presence of these antibodies and confirm whether the person is infected or not.
The correct answer is the evolution of multicellular life. The evolution of multicellular was the most important event happened during the creation of the ozone layer. All of type of the organisms had evolved over time.
Explanation: The two finches eat different kinds of food. The woodpecker finch eats insects and the large ground finch eats seeds. They do not compete for the same resources.
