The organisms that do not have a defined nucleus or organelles are classified in to _______ Kingdom.

Explanation:
Organisms that do not have a true (well-defined) nucleus or membrane-bound organelles are called prokaryotes. In the five-kingdom classification proposed by Robert H. Whittaker, all prokaryotic organisms are placed in the Monera kingdom.

Examples of Monera include bacteria and cyanobacteria (blue-green algae).

Other options:

• Fungi – Eukaryotic organisms with a true nucleus.
• Protista – Mostly unicellular eukaryotes with a true nucleus.
• Plantae – Multicellular eukaryotic plants with a true nucleus.

Correct Answer: Monera / मोनेरा