According to______ level, canned foods include low-acid foods, medium acidity foods, and high- acid foods.

If the pH value of foods is in the range of 3.7 to 4.5, we can call this kind of foods as food. A: medium acidity B: low-acid foods C: high- acid foods D: None of the above

The common name of tetradecanoic acid is A: lauric acid B: myristic acid C: stearic acid D: formic acid

Analog of sulfonamide is (    ). A: folic acid (FA) B: dihydrofolic acid (DHFA) C: tetrahydrofolic acid (THFA)  D: paraaminobenzoic acid (PABA)  E: glutamate

The following metabolites are involved in both the TCA cycle and the glyoxylate cycle except: A: citric acid B: succinate acid C: fumaric acid D: malic acid

The important substance for the special flavor of beef is ( ) in beef. A: Benzoic acid B: pyruvate C: fatty acid D: amino acid

Mercury freezes if it is cooled to＿. A: a too low temperature B: too low temperature C: a low too temperature D: too low a temperature

Which of the following statements are TRUE？ A: DHA maintains normal vision and promotes brain development of infants B: Linoleic acid and arachidonic acid mainly come from vegetable oil C: Linoleic acid and arachidonic acid regulate blood lipids, participate in phospholipid formation, promote growth, development and pregnancy D: α linolenic acid is the source of EPA and DHA

According to the scientists, life came from ___________. A: combination of energy and biochemical materials B: combination of nucleic acid and amino molecules C: nucleic acid molecules D: amino acid molecules

In food, the best ratio of saturated fatty acid, monounsaturated fatty acids, polyunsaturated fatty acid should be ( )