Answer:
Skeletal system
Explanation:
the bones of the skeleton protect the internal organs and reduce the risk of injury on impact. For example, the cranium protects the brain, the ribs offer protection to the heart and lungs, the vertebrae protect the spinal cord and the pelvis offers protection to the sensitive reproductive organs.
Well, you failed to mention which one is the recessive trait in this instance. But, let’s say red hair is recessive, denoted by r and brown hair is dominant denoted by R. Mom is rr and dad is RR. All children are going to be Rr and so heterozygous. They will all carry the trait for red hair but will express brown hair themselves, so 0% probability of having a child with red hair from the initial parents
Answer: Mutation
Explanation: Mutation is a change in DNA sequence, it may occur due to error when the DNA is copied or it can arise from various environmental factors such as exposure to chemicals, UV radiation, Highly infectious microbes.
Mutation maybe spontaneous. Acquired mutations occur at some point in a person's life and are present only in certain cells, not in every cell in the body while some may target a tissue, an organ or an entire system.