The only possibility of the daughter being colour blind is where both parents have a recessive gene for colour blindness with the father being colour blind as well. so assuming the recessive allele is Xc, then the genotype of the mother is XCXc, where she has a normal colour vision and the father's genotype is XcY, where he is colour blind.
I think observation and measurable.
Answer:
A producer. For example in a common food chain, grass->grasshopper->mouse->snake->eagle. The grasshopper eats grass which is a producer so if there aren't anymore insects like grasshoppers, then the grass grows more.
Identical twins have 100% of alleles in common.