An estimated of adults older than 50 have atrophic gastritis, making them vulnerable to b12 deficiency. a. 5 to 10% b. 50 to 75% c. 30 to 40% d. 40 to 50% e. 10 to 30%

Some birds look for food near cattle and other livestock. the movement of the cattle churns up the ground, making insects available to the birds. the cattle appear to be unaffected by the presence of the birds. what kind of relationship exists between the birds and the cattle? o a. parasitism o b. commensalism o c. predation o d. mutualism