The answer is macrophages. They either actively invade these leukocytes or are phagocytosed, divide in the cells and cause lysis. The promastigotes that invade these leucocytes are transformed into amastigotes in the macrophages. These amastigotes continue attacking other healthy macrophages while others migrate to the mid gut.
They can survive through homeostasis, the balancing of the internal temperature of the cell. <span />
That would be an isotonic solution
Endocrine Signaling
Signals from distant cells are called endocrine signals; they originate from endocrine cells. In the body, many endocrine cells are located in endocrine glands, such as the thyroid gland, the hypothalamus, and the pituitary gland.
A. umbilical cord is the answer