What are the chances that their offspring will have sickle cell anemia?

Given the autosomal recessive nature of the transmission of this disease, the probability of giving birth to a sickle cell child is 100% if both parents are sick with sickle cell disease, 50% if one of the parents is sickle cell while the other carries the sickle cell trait, 25% if both parents carry the sickle cell trait, and is zero if one parent is healthy - even if the other parent is sickle cell.

It is an inherited disease and a person who receives a gene for sickle cell disease from one parent and a normal gene from another parent leads to the condition called sickle cell trait. There are one in four which is about 25% chance that any given child could be born with sickle cell anemia if both the parents have sickle cell trait but there are also possibilities that one in four could be unaffected. There is a 50% chance that any given child will get the sickle cell trait therefore, it is possible to test the hemoglobin of an unborn baby.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds

the answer would be   10%