Answer:
A.Earth's early atmosphere lacked oxygen, which multicellular organisms need to break apart food
Explanation:
One important feature that led to the development of multicellular organisms was the rise of oxygen-producing photosynthetic bacteria. Prior to this development, the unicellular organisms (anaerobes) then present on Earth obtained energy from inorganic fuels.
However, with the presence of oxygen in the atmosphere, a shift was observed as organisms that could obtain energy from the reduction of energy became predominant. This unicellular aerobes later paved way for the evolution of multicellular aerobes.
Bicarbonate ion is important organic molecule in the buffering system of blood.
Hardness Smartest suggestion
You should do the original number (84) multiplied by the percentage (60) and then divide it by 100 to get it as a percentage of the original number:
(84 × 60) ÷ 100 = 50.4kg
Therefore, your answer is 50.4kg :)
