Well, it depends on what type of materials you are using. You should always consult your teacher because if you are doing chemisty, for example, then if you just throw everything in a trachcan, you never what elements or substances can react together.
The correct answer is phenotype
It would indicate infidelity, yes. Simplistically speaking, albinoism is caused by both of the genes dictating pigment bring recessive- if just one of the alleles allowed for pigment, that is the one that would have dictated the phenotype (physical appearance) of the person, because it is dominant. Thus, we can conclude that neither parent has a pigmented gene to be able to pass on to a child.
The answer is CO2=carbon dioxide
