The association between guinea worm and tissues of man is called

Step 1: Analyze the question The question asks what type of relationship exists between the guinea worm (Dracunculus medinensis) and the tissues of a human being.

Step 2: Key concepts

• Commensalism: One organism benefits and the other is neither harmed nor helped (e.g., egret and cattle).
• Parasitism: One organism (the parasite) lives in or on another (the host), gets food and shelter from it, and harms it.
• Predation: One animal hunts, kills, and eats another.
• Saprophytism: An organism feeds on dead or decaying organic matter (e.g., mushrooms, bread mold).
• Symbiosis: A close, mutually beneficial relationship (in the strict sense, mutualism).

Step 3: Apply to the guinea worm

• The guinea worm enters the body when a person drinks water containing Cyclops (water fleas) carrying its larvae.
• The larvae mature in the human's connective tissue. The adult female then migrates to the skin, usually of the legs or feet, and forms a painful blister and ulcer.
• The worm feeds on and lives in the human host, causing pain, ulcers, and infection.
• This means the worm benefits while the human is harmed. That is parasitism.

Step 4: Eliminate the other options

• Commensalism: the human is harmed, so it does not apply.
• Predation: the worm does not kill and eat the human outright.
• Saprophytism: the tissues are living, not dead.
• Symbiosis: the human gains nothing from the relationship.

Answer: B. Parasitism

Exam tip: Whenever you see a disease-causing organism living in or on a host (guinea worm, tapeworm, malaria parasite, roundworm), think parasitism. A quick memory aid is "Parasite = Pays nothing, Pains the host."