Which of the following statement is incorrect?
1. Metabolic acid-base disorders are caused by increasing the concentration of HCO3- in the ICF.
2. Metabolic acid-base disorders are caused by the reduction of fixed acids and metabolic acids.
3. Respiratory acid-base disorders result from a mismatch between CO2 generation in peripheral tissues and CO2 excretion by the lungs.
4. In respiratory acid-base disorders, the CO2 levels of the ICF is abnormal.

Which of the following best describes the expensive tissue hypothesis? brains require more energy, so the gut had to be reduced, and larger brains and tool use led to higher quality diets. increasing body size means that homo neanderthalensis had to include more fat in its diet. brains require more energy, so the gut had to be reduced as brains got bigger. brains require more fat, so the gastrointestinal viscera (gut) had to expand, and hands were needed to acquire more food.