When food is being mechanically digested, it is being (1) changed into another substance
(2) made smaller in size
(3) converted into energy
(4) excreted from the body

(2) made smaller in size

Explanation:

Mechanical digestion involves physically breaking the food into smaller pieces.

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.