Which structure of protein is amino acid sequence. d is quaternary

Cattle with brown fur and cattle with white fur will produce a reddish roan calf . when examined closely, the calf show about an even number of brown hairs and white hairs that give a reddish appearance when viewed from far away. the fact that both the brown fur allele and the white fur allele are expressed equally in the offspring is an example of

Everything that surrounds a particular organism

What is any method of measuring the age of an object or event in years, such as using atomic half-life?