What are the differences between the dominant-recessive model of inheritance compared to the co-dominance model of inheritance?

In the dominant- recessive model of inheritance, the dominant allele fully suppresses the recessive allele. As a result, heterozygous individuals produced show the effect of the dominant trait in them. For the recessive trait to occur, both the alleles of the gene should be recessive in the organism.

In co- dominance model of inheritance, the dominant allele is not fully dominant over the recessive trait. As a result, heterozygous individuals show both the dominant and recessive characteristic in them. For a dominant trait to occur, both the alleles should be dominant. For a recessive trait to occur, both the alleles should be recessive.

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus