Antenatal and postnatal screening

1

What liquid is tested during amniocentesis?

2

Why does a person need to have two copies of the cystic fibrosis allele to have cystic fibrosis?

3

What does heterozygous mean?

4

Why does a dominant allele create a higher probability of an offspring affected by a disease, such as cystic fibrosis?

5

In a genetic diagram, how is a dominant allele shown?