Who made the earliest scientific attempts to classify organisms?

Why was there a need for a change in the classification system?

$Statement-1$: Linnaeus classified plants into trees,shrubs,and herbs based on morphological characters.
$Statement-2$: Aristotle divided animals into two groups: $Anaima$ (animals without red blood) and $Enaima$ (animals with red blood).

Classification that is based on various morphological characters is known as what?

The Linnaeus system of plant classification is:

Which of the following criteria was used in the two-kingdom classification system proposed by Carolus Linnaeus?