Which of the following shows the CORRECT order of biological levels of organisation fromcomplex to simple?

Explanation

The correct order of biological organization from complex to simple is: Spleen → Leucocyte → Mitochondria → Adenine. The spleen is an organ, which is more complex than a leucocyte, a type of cell. Mitochondria are organelles within cells, and adenine is a nucleotide, a molecular component of DNA and RNA. The other options incorrectly order these structures, either starting with a simpler component or misordering the organelles and molecules.