Question

Insects have blood which

• A. Is similar to human blood in colour
• B. Circulates through the closed blood vessels
• C. Circulates in open system
• D. Contain haemoglobin as respiratory pigment

Answer 1

Answer: (C)

Circulates in open system

Insects, like all other arthropods, have an open circulatory system, whereby blood, (haemolymph), flows freely through the body cavity, (haemocoel). There is a dorsal vessel which is closed at the posterior end of the abdomen, and runs forward along the dorsal midline and opens in the head at the anterior portion. There are several chambers and openings known as ostia along the dorsal vessel where blood enters it through valves. The blood is then pumped forward to the aorta and into the body cavity.

Therefore, the correct answer is option C.