Question

a researcher investigates a blood disease carried by birds. she isolates an organism from the blood of an infected bird. she finds that the organism is unicellular and has a nucleus, a cell wall, and the ability to produce spores. what kingdom does the organism belong to?

sarcodina
archaea
bacteria
protista

Explanation:

Analyze the organism's characteristics

The problem describes an organism isolated from the blood of an infected bird with the following characteristics:

• Unicellular (single-celled)
• Has a nucleus (eukaryotic)
• Has a cell wall
• Has the ability to produce spores

Evaluate the taxonomic domains and kingdoms

Let's evaluate the given options based on these biological characteristics:

• archaea: These are prokaryotic organisms, meaning they lack a membrane-bound nucleus. This contradicts the finding of a nucleus.
• bacteria: These are also prokaryotic organisms and lack a nucleus. This contradicts the finding of a nucleus.
• sarcodina: This is a subphylum/group of amoeboid protists (within the kingdom Protista) that typically lack a rigid cell wall and do not typically form spores in this context.
• protista: This kingdom includes unicellular eukaryotic organisms. Many unicellular eukaryotes with cell walls and spore-producing capabilities (such as certain unicellular algae, slime molds, or parasitic protozoans/sporozoans) are classified under the kingdom Protista.

Determine the correct kingdom

Since the organism is unicellular and eukaryotic (has a nucleus), it cannot belong to the prokaryotic domains/kingdoms (Bacteria or Archaea). Among the eukaryotic options, "protista" is the correct kingdom classification for a unicellular eukaryote with these features.

Answer:

• sarcodina
• archaea
• bacteria
• protista (Correct answer)