In the structure of dna, which nucleotide always pairs with adenine? a) cytosine b) guanine c) thymine d) uracil

Why do we perceive objects as retaining their brightness under different lighting levels?

Body temperature is tightly regulated in mammals for example when external temperatures drop too much the body of a mammal responds by in order to its core temperature?

Which heredity condition causes a buildup of mucus in lungs and pancreas? a. cystic fibrosis b. heart disease c. huntington's disease d. sickle cell anemia