Final answer:
The Roman Catholic Church practices infant baptism mainly because it follows biblical command and believes in purging original sin from newborn children.
Step-by-step explanation:
The most accurate explanation of why the Roman Catholic Church practices infant baptism is because it follows biblical command and also believes in purging original sin from a newborn child through baptism. Infant baptism was the norm among Catholics and most Protestants because it was believed that without baptism, even a newborn who died would be denied entrance to heaven.