Final answer:
The presence of anemia in one out of five children from unaffected parents suggests that anemia is likely a recessive trait. Without display in parents, autosomal recessive inheritance implies parents are carriers and the affected child is homozygous recessive.
Step-by-step explanation:
Given that anemia is present in one out of five children from unaffected parents, we can conclude anemia is likely a recessive trait.
In the case of autosomal recessive inheritance, both parents would not show the disorder as they would be carriers with one normal and one affected allele (heterozygous). For the recessive anemia to be expressed, the child must inherit the affected allele from both parents, leading to a homozygous recessive genotype. As such disorders manifest only when an individual carries two copies of the recessive allele, this would explain the single affected child amongst five.
Since the inheritance of the anemia trait does not appear to be linked to sex or show a pattern consistent with dominant inheritance (where one parent with the dominant allele would be affected), and without indications of polygenic traits, the most likely explanation is a recessive trait. To further confirm this, one could look for patterns of inheritance over multiple generations or the presence of anemia in other relatives who may be carriers. Other relevant details such as the specific nature of the anemia or if it is part of a syndrome could help pinpoint the precise inheritance pattern.