A person with AIDS may take longer than a healthy person to recover from a Salmonella infection. Explain why.

Which of the following birds remained ancient looking in the miocene epoch? a. crows b. owls c. grouses d. none of the above

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons

What type of appendages do sponges cnidarians roundworms annelids mollusks arthropods echinoderms and vertebrate have? jointed, not jointed, absent