Introduction:
The blood of an earthworm, also known as hemolymph, and the blood of a human, known as blood, have distinct differences in terms of composition, function, and structure.

Composition:
- Earthworm Blood: The blood of an earthworm, called hemolymph, is not red but rather colorless. It contains various cells, including amebocytes, coelomocytes, and chloragocytes. Hemolymph also contains proteins, enzymes, and inorganic salts.
- Human Blood: Human blood is red due to the presence of red blood cells. It consists of plasma, red blood cells, white blood cells, and platelets. Plasma is a yellowish fluid that carries nutrients, hormones, and waste products. Red blood cells contain hemoglobin, which gives blood its red color.

Function:
- Earthworm Blood: The primary function of earthworm blood is to transport oxygen and nutrients to different parts of the body. It also helps in removing waste products from cells.
- Human Blood: Human blood serves numerous functions, including transportation of oxygen, nutrients, hormones, and waste products. It helps regulate body temperature, pH balance, and immune responses. Blood also plays a vital role in blood clotting to prevent excessive bleeding.

Structure:
- Earthworm Blood: Hemolymph in earthworms circulates freely within the body cavity called the coelom. It flows in sinuses and spaces around organs.
- Human Blood: Human blood circulates within a closed circulatory system, consisting of blood vessels, including arteries, veins, and capillaries. It is pumped by the heart and flows in a continuous loop.

Transportation System:
- Earthworm Blood: The circulatory system of earthworms is relatively simple. Hemolymph moves through the coelom and reaches organs directly.
- Human Blood: In humans, blood flows through a complex network of blood vessels, ensuring efficient transport to cells and organs throughout the body. It is pumped by the heart, which propels oxygenated blood to tissues and returns deoxygenated blood to the lungs for oxygen replenishment.

Conclusion:
In summary, the blood of an earthworm (hemolymph) differs from human blood in terms of composition, function, structure, and transportation system. Earthworm blood, being colorless, circulates freely in the coelom, while human blood, with its distinct red color, flows through a closed circulatory system. Both types of blood play crucial roles in their respective organisms, facilitating the transportation of essential substances and maintaining overall physiological balance.

Blood of human : matured RBC has no nuclei , blood of earthworms : has nuclei in its RBC.