What is a characteristic of aging and the immune system? a. immunity in older people does not seem to be affected by regular exercise. b. immune function does not decline with age in people who maintain good nutrition. c. antibiotics are often ineffective in treating infections in older people who have deficient immune systems. d. in the united states, infectious diseases are a minor cause of deaths in the elderly?

Group control group #1 experimental group yes yes yes control group #2 no new drug orange juice bed rest no yes no yes ves which of the following is the best explanation of why a second control group was included in this experiment? o a. to provide the volunteers in the study with something to drink o b. to prove that the common cold cannot be cured c. to confuse anyone who is trying to steal their new drug and sell it as their own invention o d. to researchers conclude that results are related to the new drug and not to the orange juice submit e previous

Ivan is looking at a cross section of a stem taken from a vascular plant. he sees two different types of vascular tissue: the xylem, which is closer to the center of the stem, and the phloem, located around the xylem, closer to the outside of the stem. how do these two structures work together in a living plant?

26 a medida que cambia el clima, ¿qué tipo de reproducción más probablemente de a una especie mayores posibilidades de supervivencia?