The pH of water determines the solubility (amount that can be dissolved in the water) and biological availability (amount that can be utilized by aquatic life) of chemical constituents such as nutrients (phosphorus, nitrogen, and carbon) and heavy metals (lead, copper, cadmium, etc.).
No clue as to find out how many professional players are in those countries. Baseball in the US This information is for the US only: For Major League Players - There are 30 Major League teams each with a 40 man roster. 30 x 40 = 1200 Then, on average, each team has 6 farm teams in its system with a roster of 25 to 30 players. So 6 x 30 x 30 = 5400.
Estimated probability of competing in professional baseball. MLB draft data from 2016. There were 1,206 draft picks in that year; 695 of those picked were from NCAA schools (source: MLB Draft Tracker 2016). Of the 695, Division I student-athletes comprised 595 of those chosen, Division II provided 80 and Division III had 20.