The words which comes in the blanks are NADH and electron.
<span>A molecule generated in both glycolysis and krebs cycle, called NADH , donates electrons to the first protein in the electron transport chain.
Kerbs cycle is also known as citric Acid cycle or tri-carboxylic acid cycle.
</span>NADH<span>, stands for nicotinamide adenine dinucleotide, and it is an important pyridine nucleotide.</span>
Temperature and oxygen level
Photosynthesis and cellular respiration are important components of the carbon cycle, in which carbon is exchanged among the biosphere, atmosphere, oceans, and geosphere through chemical, physical, geological, and biological processes.
Look up Dawrin's theory of evolution. Basically, fossil records show how life forms change over time through evolution.