Fossil evidence indicates that horses have gradually increased in size over geologic time. Which of the following terms best describes this?

Fossil evidence indicates that horses have gradually increased in size over geologic time. Which of the following terms best describes this?

فوسل شواہد سے پتہ چلتا ہے کہ جغرافیائی وقت کے ساتھ گھوڑوں کے سائز میں بتدریج اضافہ ہوا ہے۔ مندرجہ ذیل میں سے کون سی اصطلاح اس کی بہترین وضاحت کرتی ہے؟
Explanation
  • Directional selection occurs when one extreme phenotype is favored.
  • It leading to a shift in the population's traits over time.
  • The increase in horse size over geologic time is an example of this type of selection.