Explanation:
In the majority of cases, the extra copy of chromosome 21 comes from the mother in the egg.
In a small percentage (less than 5%) of cases, the extra copy of chromosome 21 comes from the father through the sperm.
In the remaining cases, the error occurs after fertilization, as the embryo grows.
Mitosis is when the cell divides
Answer;
A. Movement in his lower extremities
Explanation;
-The 1st lumbar vertebra or the L1 vertebra is the smallest and most superior of the lumbar vertebrae. As the first vertebra in the lumbar region, the L1 vertebra bears the weight of the upper body and acts as a transition between the thoracic and lumbar vertebrae.
-The lumbar vertebrae contain spinal cord tissue and nerves which control communication between the brain and the legs.
Just post them in like 2 or 3 post like maybe 15 or 25 questions per post, if anyone knows the answer, then they will just answer it below!
Answer:
I don't know the ans then also,pls mark me as brainliest
Explanation:
