Bronchitis often progresses to a more severe lung condition called which was the leading world killer around 1900 a. d.

Synovial fluid serves as a lubricant to prevent friction between two parts that move on each other such as in the case of and bones.

Which of the following statements describes the lysogenic cycle of lambda (λ) phage? a) after infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses. b) most of the prophage genes are activated by the product of a particular prophage gene. c) the phage genome replicates along with the host genome. d) the phage dna is copied and exits the cell as a phage.

Which of the following best reflects what we know about how the flu virus moves between species? a) the flu virus in a pig is mutated and replicated in alternate arrangements so that humans who eat the pig products can be infected. b) a flu virus from a human epidemic or pandemic infects birds; the birds replicate the virus differently and then pass it back to humans. c) an influenza virus gains new sequences of dna from another virus, such as a herpesvirus; this enables it to be transmitted to a human host. d) an animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates, the virus is passed to a new species such as a bird, and the virus mutates again and can now be transmitted to humans.