Identify the option that does not exhibit a parasitic relationship.

The correct option is Female Anopheles.

To understand why this is the correct answer, let us analyze the nature of a parasitic relationship and evaluate each option step-by-step:
A parasitic relationship (parasitism) is an interaction between two different species where one organism (the parasite) lives on or inside another organism (the host) for a significant portion of its life cycle, deriving nutrients and shelter at the expense of the host, usually causing some degree of harm to the host without immediately killing it.

Step-by-Step Analysis of the Options:

1. Head lice in humans:
Head lice are tiny insect parasites that live on the human scalp. They feed on human blood and rely completely on the human host for survival, warmth, and reproduction, causing itching and irritation. Thus, this is a clear example of a parasitic relationship.

2. Cuscuta on a mango tree:
Cuscuta (commonly known as dodder) is a parasitic plant that lacks chlorophyll and leaf structure. It wraps around a host plant, such as a mango tree, and produces specialized root-like structures called haustoria. These structures penetrate the host's vascular tissues to draw water, minerals, and organic nutrients. This is a classic parasitic relationship.

3. Ticks on dogs:
Ticks are external parasites (ectoparasites) that attach themselves to the skin of dogs. They feed on the host's blood to grow and complete their life cycles, often transmitting pathogens. Since they depend directly on the host dog for sustenance while harming it, this represents a parasitic relationship.

4. Female Anopheles:
The female Anopheles mosquito feeds on human blood, but it does not live on or inside the human host. It requires blood meals solely to obtain the proteins and nutrients necessary to develop and mature its eggs, rather than for its own personal survival (as adult mosquitoes primary feed on plant juices and nectar for energy). Because it is a free-living insect that visits the host briefly for egg reproduction rather than living on the host as a parasite, it does not exhibit a classic parasitic relationship. Instead, it is considered a blood-feeding pest or a vector for diseases (like malaria).

Therefore, the Female Anopheles is the option that does not exhibit a parasitic relationship.