Complex sentence: If the extra chromosome is absorbed into a polar body rather than being passed into the oocyte, trisomy can be avoided; whether this is a chance event or is some way influenced by the microenvironment is unclear.
Split into simpler sentences: If the extra chromosome is absorbed into a polar body rather than being passed into the oocyte, trisomy can be avoided. Whether this is a chance event or is some way influenced by the microenvironment is unclear.