Anything in the environment that can cause a mutation is called as a mutagen.
Environmental mutagens include:
radiations, chemical, infectious agents, extreme heat.
The environment we live in has a real impact on whether we experience genetic mutations. The quality of water we drink and the air we breathe can actually effect the integrity of our DNA. Our bodies are designed to correct any mistakes, but dangers from the environment can increase our chances of ending up with a mutation.
Cyclins are a family of proteins that control the progression of cells through the cell cycle by activating cyclin-dependent kinase (Cdk) enzymes.
So A. Is correct
Juipter was almost massive enough to become a star.
The deep ocean vessels habe very thick windows and walls because the at very depth ocean the pressure is very high so the vessels should have very thick windows and walls to withstand the great pressure that is applied on the vessel. this also to insure the safety of the people inside it.