Question

1. chromosomes are made up of two identical sister a) nuclei b) genes c) chromatids d) cells e) chloroplasts

Explanation:

Chromosomes are composed of two identical sister chromatids which are formed after DNA replication during the S - phase of the cell - cycle. Nuclei are cell organelles that contain chromosomes, genes are segments of DNA on chromosomes, cells are the basic unit of life that contain nuclei, and chloroplasts are plant cell organelles involved in photosynthesis.

Answer:

c) Chromatids