Which of the following organisms requires an additional non-human host to complete its life cycle?

• A. Escherichia coli (E. coli)
• B. Plasmodium species (malaria parasite)
• C. Saccharomyces cerevisiae (yeast)
• D. Homo sapiens (humans)

Answer: (B)

Verified step by step guidance

1. Understand the life cycle of each organism listed in the problem. Determine whether the organism requires a non-human host to complete its life cycle.
2. Escherichia coli (E. coli): This is a bacterium commonly found in the intestines of humans and other animals. It does not require a non-human host to complete its life cycle, as it can reproduce independently in its environment.
3. Saccharomyces cerevisiae (yeast): This is a single-celled fungus used in baking and brewing. It reproduces asexually or sexually and does not require a non-human host to complete its life cycle.
4. Homo sapiens (humans): Humans are multicellular organisms that reproduce sexually. They do not require a non-human host to complete their life cycle.
5. Plasmodium species (malaria parasite): This is a protozoan parasite that requires both a human host and a non-human host (typically a mosquito from the genus *Anopheles*) to complete its life cycle. The mosquito serves as the vector for transmission and is essential for the parasite's development and reproduction.