An example of a single hormone that can exert effects in different tissues is erythropoietin. erythropoietin is made in the kidney and stimulates the bone marrow to produce: 1. platelets.
2. natural killer cells.
3. red blood cells.
4. mast cells.

Red blood cells (Ans. 3)

Explanation:

Erythropoietin or EPO is a hormone which is also called as haemopoietin, it is a glycoprotein cytokine. One unique characteristic of hormones is that single hormone helps to apply various effects in different tissues.

For example erythropoietin which is known as traditional circulating hormone is made in the kidney, on the other hand at the same time it produces red blood cells (erythropoiesis) in the bone marrow.