In which initial stage of animal cells does glucose break down?

Identify the chemical compounds represented by the following formulas:
$(1)$ $CH_3CH(OH)COOH$
$(2)$ $CH_3COCOOH$

How is $PGA$ formed from $PGAL$?

During glycolysis or the $EMP$ pathway,how many net $ATP$ molecules are produced directly from one mole of glucose (in $ATP$)?

Interconversion of glyceraldehyde-$3$-phosphate and dihydroxyacetone phosphate is catalysed by which enzyme?

The common step of both aerobic and anaerobic respiration is: