Which of the following is the Fischer projection of $L$-threonine (also known as $(2S, 3R)-2$-amino-$3$-hydroxybutanoic acid)?

The number of six-membered and five-membered rings present in norethindrone (a synthetic progesterone) are respectively:

Which of the following matches is wrong?

Which of the following statements are correct?
a) In maltose,$C-1$ of one $\alpha-D$-glucose is linked to $C-4$ of second $\alpha-D$-glucose.
b) Quaternary structure of protein represents spatial arrangement of two or more polypeptide chains with respect to each other.
c) Nucleotide units in a nucleic acid are joined to each other through a phosphodiester linkage.
d) Abnormally low level of thyroxine leads to hypothyroidism.

During the process of aerobic respiration,acetyl co-enzyme $A$ is formed from which of the following?

Identify the statement which is not correct from the following.
$(i)$ Carbohydrates are stored as glycogen in animals.
$(ii)$ In glycylalanine,the carbonyl group of peptide bond belongs to alanine.
$(iii)$ Base - sugar - phosphate unit is known as nucleoside.
$(iv)$ Obesity is due to hypothyroidism.
The correct answer is