Presence of chromosomes: Chromosomes are always present in cells. If a cell is deficient in chromosomes, new cells produced from that cell will be deficient in chromosomes.
Pairing of Homologous Chromosomes: Homologous chromosomes are paired. That is, one small chromosome is linked to another small chromosome.
Independent Distribution of Chromosome Pairs: Chromosomes are arranged in pairs in organisms. Pairing is done independently.
Qualitative differences between chromosome pairs: Each chromosome contains genes controlling different traits. One chromosome causes normal cell growth and the other causes abnormal cell growth.
Sex determination: The sex of an organism is determined by sex chromosomes or allosomes.
Restoration: Fertilization restores the chromosome number in diploid cells.
Physical Basis of Heredity: Hereditary factors or genes are located on chromosomes. Hence it is called the physical basis of heredity.