Read the following statements about the nucleus and the chromosomes. (i) The outer membrane of the nuclear envelope usually stays continuous with the endoplasmic reticulum and bears ribosomes. (ii) Nuclear pores let RNA and protein molecules move in both directions between the nucleus and the cytoplasm. (iii) Chromatin contains DNA, some basic proteins called histones, some non-histone proteins and also RNA. (iv) In an acrocentric chromosome, the centromere lies exactly at one end of the chromosome. (v) Larger and more numerous nucleoli are present in cells that are actively carrying out protein synthesis. (vi) A single human cell has about $2\ \text{m}$ of DNA, shared among $23$ chromosomes. How many of the statements above are correct?