Why is a ring of life more appropriate to describe the relationship between archaea bacteria and eukaryotes than a tree of life

Jerry wants to consume no more than 45% of his calories from carbohydrates. calculate his requirement for calories from carbohydrates based on a 2,500 kcal per day intake.

Despite the differences in mature plant cells, all of them are derived from meristem cells. the three major types of tissue systems develop from the meristem. meristems develop cells in all but which tissue?

Which direction does the energy flow in this energy pyramid ?