Answer:
Chromosomes contain very large genetic information which would take many hours to replicate with only one origin.
Explanation:
Human cells are eukaryotes, meaning that the genetic information is compressed in chromosomes, that at the same time are contained in the nucleus. As the replication requires all the genetic information to be copied, the length of it would take several hours to complete this task. Therefore, with many origins of replication, this process happens faster and more effectively.
When antigens (foreign substances that invade the body) are detected, several types of cells work together to recognize them and respond. These cells trigger the B lymphocytes to produce antibodies, which are specialized proteins that lock onto specific antigens
The Circulatory system does not have an excretory organ.
The answer is the Circulatory system.