Not sure sorry somone awnser this
Answer:
excretory system and circulatory system
Explanation:
Blood is part of circulatory system and as it move through various organs it exchanges the gases i.e give oxygen to the cell and take carbon dioxide from them. After taking CO2, the blood becomes impure and hence it passes through the kidney before going to the heart. Kidney is part of excretory system which removes carbon dioxide from blood and thus purifies it.
Dominant refers to the relationship between two versions of a gene. Individuals receive two versions of each gene, known as alleles, from each parent. If the alleles of a gene are different, one allele will be expressed; it is the dominant gene. The effect of the other allele, called recessive, is masked.
