Among the natural defenses present in tears is the protein lactoferrin. as youcan infer from its name, it is also present in milk and other body secretions, andits function involves binding iron ions. the presence of lactoferrin in tears isprotective against bacterial infection . all pathogens must acquire iron from their environment andlactoferrin ensures that the iron concentration is low. b. pathogens with magnetosomes will be segregated from the eye tissueand swept away by the tears. c. free iron serves as an immune signal to recruit t cells to the eye. d. in the presence of lysozyme, as found in tears, the proteins form aprotective barrier on the lens.

Which of the following is true of photosynthesis? a)carbon dioxide is a reactant b)water is a product c)most reactions within this process are exothermic d)oxygen is a reactant

Read the following scenario to answer the following question. in some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called "ligers." male ligers are sterile but some female ligers are fertile. in the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences. applying the biological species concept, the sterility of ligers reveals that a. lions are probably a subspecies of tigers b. tigers and lions are the same species c. a new species called "ligers" is forming d. tigers and lions are separate species

Which way do the nitrogenous bases in dna pair up? a. a and g; t and c b. a and c; t and g c. a and t; g and c d. a and a; t and t; g and g; c and c