The numerical taxonomy of plants is based on which of the following?

Option 1 : All observable characteristics

The correct answer is All observable characteristics.

• Numerical taxonomy is a biological systematics classification system that deals with the numerical grouping of taxonomic units based on their character states.
• Its goal is to establish a taxonomy utilizing numerical algorithms such as cluster analysis rather than subjective property evaluation.
• Robert R. Sokal and Peter H. A. Sneath first proposed the idea in 1963, and the same authors later expanded on it.
• They divided the field into phenetics, which classifies organisms based on overall similarity patterns, and cladistics, which classifies organisms based on the branching patterns of the taxa's estimated evolutionary history. 
• The relationships between organisms are mathematically established, usually with the help of a computer, and their characteristics are given equal weight. 
• Thus, the numerical taxonomy of plants is based on all observable characteristics.