The answer would be "<span>Cyclins are proteins that regulate when and how often a cell divides". Cyclins belong to a family of proteins that control the progression of a cell through its respective cell cycle. This is initiated by activating cyclin-dependent kinase (CDK) enzymes which regulate </span>transcription of RNA and process mRNA during mitosis.
Sun is the source of energy for life on earth.
Answer Sun -d)
