TRUE OR FALSE (each sentence) 1. t/f Macrophages and dendritic cells can both be antigen-presenting cells.

2. t/f Complement proteins are antibodies produced by skin cells.

3. t/f Dendritic cells are the histamine-producing cells of the immune system.

4. t/f Stomach acid is one of our natural defenses against bacteria in food.

5. t/f Cytokines are molecules that cut holes in bacterial membranes.

6. t/f There are different Toll-Like Receptors for bacteria and viruses.

the correct answer is: d. the saltine and pretzel are made of flour, yeast, and baking soda, and salt. the pecan contains no flour but it does contain fats. the pecan is a nut that can be consumed as a healthy snack. first of all, pecans are a source of fat (monounsaturated fat), but they provide less fat than some other nuts. pecans are a rich source of dietary fiber, manganese magnesium, phosphorus, thiamin, vitamin e…

c.more precipitation,but only when emission levels.

answer; both surfaces of the membrane are nonpermeable