Answer:
Explanation: In other words, adenine and thymine are complementary base pairs, and cytosine and guanine are also complementary base pairs. This is the basis for Chargaff's rule; because of their complementarity, there is as much adenine as thymine in a DNA molecule and as much guanine as cytosine.
I don't know about the other ones but the sky is blue because molecules move from the sun than the red from the sun. The blue has separated from the sun.
Answer:
the immune system needs B cells and memory B cells form into memory cells so that remember the same pathogen and the antibody used to take it down for faster antibody production in future infections when most of the same antigens infect the body again.
Explanation:
When the body senses foreign substances like antigens, the immune system works to recognize the antigens and get rid of them. B Cells that have a certain antibody codes/proteins for the specific antigen are triggered or activated by T cells to make the specific antibodies, or immunoglobulins, to use against the antigens, by locking onto the antigen and putting the antibodies into the antigen directly.
C. 20 because 39-19 is 20 so there are 20 neutrons and the atomic number is the same as number of protons and electrons.