The helical structure of proteins is stabilised by
peptide bonds
dipeptide bond
hydrogen bond
van der Waal's forces
Lactose sugar is formed from
d-galactose
d-glucose
d-galactose and d-glucose
d-glucose and d-fructose
C.
d-galactose and d-glucose
Lactose sugar contains d-galactose and d-glucose. In it glycosidic linkage is formed between galactose and glucose.