Why is natural selection considered a probabilistic process?

Hereditary changes in individuals of the same population occur in different directions and can be very diverse under the same environmental conditions. Therefore, natural selection is a probabilistic process. Acting in different directions, it can lead to different results. However, all of them provide organisms (both species and populations) with preferential survival and reproduction in specific environmental conditions.
Natural selection is a directed but probabilistic process.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.