Which of the following statements is TRUE? A. A piece of DNA is often very long, containing many genes, while a piece of RNA is
often very short, containing only one gene
B. DNA never leaves the nucleus of a cell, but RNA can be found inside or outside the
nucleus
C. DNA contains a nitrogenous base called thymine, but RNA contains no thymine
D. All of the above are true

All but one describes an effect of aging on the digestive system. a) decreased acid secretion b) decreased elasticity of stomach c) capacity to resist damage decreases d) food remains in stomach for less time

In general, characteristics that an organism survive and reproduce become more common in a population over time. what mechanism of evolution cause this change?

Red blood cells are responsible for transporting oxygen in the blood. people with sickle cell anemia were born with a defective gene that results in sickle-shaped red blood cells. individuals with the disease often suffer pain in their extremities due to the build-up of these cells causing blockages in the blood vessels. the shape of the blood cells also reduces the amount of oxygen transported in the blood.