Which of the following processes occurs in glycolysis?

In glycolysis,the end product is

The net gain of $ATP$ molecules during glycolysis is ......... .

The first stage in respiration is:

Describe the process represented by the equation: $C_6H_{12}O_6 \to 2CH_3COCOOH + 2ATP + 2NADH + 2H^+$

Select the correct sequence of reactions in glycolysis:
$(a)$ $3$-phosphoglyceraldehyde $\rightarrow$ $1,3$-biphosphoglycerate
$(b)$ $3$-phosphoglyceric acid $\rightarrow$ $2$-phosphoglycerate
$(c)$ $1,3$-biphosphoglyceric acid $\rightarrow$ $3$-phosphoglyceric acid
$(d)$ Splitting of $1,6$-fructose biphosphate to dihydroxyacetone phosphate and $3$-phosphoglyceraldehyde