The human microbiome, which consists of approximately 100 trillion bacteria per person, has been significantly changing over the past several decades. (doctorakil.com)
As a consequence, the level of salt in our environments has gradually risen over the past several decades. (news.rpi.edu)
The majority of the new students in higher education over the past several decades attend large public institutions, which have long since exhausted their economies of scale. (educationnext.org)