Answer:
The addition of an extra chromosome usually occurs spontaneously during conception. The cause of this is unknown and prevention is not possible. The most important risk factor for trisomy conditions is maternal age. Women in their late 30s and 40s have a higher chance of trisomy conditions occurring.
Answer:
Blood, the heart pumps oxygen-poor blood to the lungs to be oxygenated.
Explanation:
:) Merry Christmas!
Sexual reproduction. Like most mammals, giraffes produce sexually, meaning that both parents contribute to the DNA of the offspring.
Due, to know life on the moon there would be nothing to mess with the footprint, but the main reason why these footprints are going to last centuries is because "there is no weather." Since how there is no weather on the moon which means no wind there is no factors that could affect the footprint.
Hope this helps!