Characteristics and Examples of Fossil Formation. The many different ways organisms are preserved gives fossils different characteristics. Let's explore a few ways fossils can form. Permineralization is when an organism dies and sediment enters the body, filling in the pores of a leaf, or a bone or a shell.
As you can see, for 2 people with Down syndrome having babies, the chances are as follows: -25% chance their child will be typical (no Down syndrome). -50% chance their baby will have Down syndrome. -25% chance there will be no viable pregnancy.
The most common form of Down syndrome is known as Trisomy 21, a condition where individuals have 47 chromosomes in each cell instead of 46. This is caused by an error in cell division called nondisjunction, which leaves a sperm or egg cell with an extra copy of chromosome 21 before or at conception.he only factor known to affect the probability of having a baby with Down syndrome is maternal age. That is, less than one in 1,000 pregnancies for mothers less than 30 years of age results in a baby with Down syndrome. For mothers who are 44 years of age, about 1 in 35 pregnancies results in a baby with Down syndrome.