The kingdom-level classification system is now preceded by the category, which is based on evolutionary and biochemical characteristics of all living organisms.

Domain

Explanation:

It is common to find in textbooks the classification of living organisms into five kingdoms: Kingdom Monera, Kingdom Protista, Kingdom Fungi, Kingdom Plantae and Kingdom Animalia. It is now known that this classification has some serious flaws and that some kingdoms are no longer considered.

A widely accepted classification today is one that comprises one category above the kingdoms: domains. This classification was proposed by Carl Woese in 1977 and is based on molecular phylogeny data. According to Woese, there are three domains: Archaea Domain, Bacteria Domain, and Eukarya Domain.

They perform checkpoints and regulate/control the cell cycle.

Explanation:

Cyclin/CDK complexes are known to regulate both mitotic and meiotic cell cycles. Some processes are shared by both forms of cell division, however the process known as meiosis differs in terms of its features and needs. Following two rounds of cell division in succession, meiosis is characterized by the replication of DNA.