Answer:
Molecular evidence
Explanation:
Earlier archaea were considered as bacteria because they show some similarities with bacteria like binary fission as mode of reproduction, lack of a nucleus, etc.
Later Carl Woese separated bacteria in a different domain and divide prokaryote into two domains called bacteria and archaea. He separated archaea from bacteria on molecules evidence.
He compaired rRNA sequence between bacteria and archaea and observed that they both differ in rRNA sequence which allowed him to make a separate domain for archaea.
Ecological efficiency is the term used to describe how much energy will be passed from lower food pyramid level into the higher level. The amount of energy in primary level will be much higher than tertiary. The difference of level of tertiary(3) with primary(1) would be two level.
Assuming that the ecological efficiency is 10%, then the <span>primary consumer level would be: 50 kcal * 10^(3-1)= 5000 kcal</span>