What is the unit formed by eight molecules of histone called?

Which of the following statements is correct?

The unit of inheritance is.

Identify the correct features of $DNA$ from the following statements:
$(i)$ It is made of two polynucleotide chains.
(ii) The backbone is constituted by sugar and phosphate.
(iii) The two chains have anti-parallel polarity.
(iv) The bases in the two strands are linked through $H$-bonds.
$(v)$ Both chains are coiled in a right-handed fashion.

The two strands of a double helix model of $DNA$ are held together by hydrogen bonds between

Which of the following options is incorrect regarding $DNA$ base pairing rules (Chargaff's rules)?