The feeding relationship that exists between a tick and a cow is?

Step 1: Analyze the question The question asks about the feeding relationship between a tick and a cow. This is about types of symbiotic or feeding associations between organisms.

Step 2: Explain the concepts

• Parasitism: One organism (the parasite) lives on or in another (the host), feeds on it, and harms it. The parasite benefits while the host loses.
• Mechanism: Not a feeding relationship. It refers to how something works.
• Saprophytism: Feeding on dead or decaying organic matter (e.g., mushrooms, moulds).
• Commensalism: One organism benefits while the other is neither helped nor harmed (e.g., an epiphyte growing on a tree).

Step 3: Apply to the question A tick attaches itself to the skin of a cow and sucks its blood. The tick gains food and shelter. The cow loses blood, can become weak or anaemic, and may get diseases such as tick-borne fever (e.g., babesiosis). So the cow is harmed.

• Is the cow dead or decaying? No, so it is not saprophytism.
• Is the cow unaffected? No, it is harmed, so it is not commensalism.
• "Mechanism" is not a biological feeding relationship.

The tick is an ectoparasite (it lives on the outside of its host), and the cow is the host.

Step 4: Answer The correct option is A. parasitism.

Exam tip: Ask yourself, "Who benefits, and who is harmed?"

• Benefits and harms = parasitism (tick, mosquito, lice, tapeworm)
• Benefits and no harm = commensalism
• Both benefit = mutualism
• Feeds on dead matter = saprophytism