Single celled organisms are able to maintain internal stability becuse they

Answer;

They contain structures that perform life-functions

Single celled organisms are able to maintain internal stability because they contain structures that perform life-functions.

Explanation;

Single cell organisms are those organisms that contain only one cell unlike multicellular organisms that contain many number of cells.

Single cell organisms include bacteria, archaea and protozoa.

Single cell organisms live and carry out all their life processes in one single cell. Most of them are microscopic; examples are Euglena, green algae, etc.

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.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".