Answer:
the answer is A. Don't expect a explanation because this question is too easy for me to explain . Have a nice day!
Answer:
Cyclin is a family of proteins that controls the progression of a cell through the cell cycle by activating cyclin-dependent kinase (CDK) enzymes or group of enzymes required for synthesis of cell cycle.
Barking when frightened
Explanation
The others require you to teach the dog how to do it but I dog doesn’t need teaching to bark it comes naturally
