Answer:
Instead of a brain, echinoderms have a ring of nerves located around their mouth area that governs their nervous responses. This ring coordinates their motion, their eating, basically anything that requires nerve control.
Explanation:
B. CO2 levels in the atmosphere could increase and contribute to global warming problems.
Answer:
B. The father did not contribute a sex chromosome to his daughter due to nondisjunction of the sex chromosomes. The daughter is XO and her only X chromosome came from her mother, who was a carrier.
A.The mother's X chromosomes failed to separate during meiosis, and the daughter inherited two X chromosomes with the Lesch-Nyhan mutation. The father contributed no sex chromosomes.
Explanation:
As seen in the question above, a little girl was diagnosed with Lesch-Nyhan syndrome, which is an X-linked recessive condition caused by a mutation in the HPRT1 gene responsible for purine metabolism.
The little girl's parents do not have the syndrome, and no one in the little girl's paternal family presented this syndrome, however, we know that the maternal grandfather of the little girl's mother had the syndrome, which means that it was the mother's genetic material that contributed to the development of the syndrome in the little girl. This was because the little girl did not receive any X chromosomes from her father, but she inherited the two X chromosomes from her mother that coded for the Lesch-Nyhan mutation. This happened because the mother's X chromosome disjuction did not occur during meiosis I.
As shown above, the father did not contribute any sex chromosomes to his daughter, which means that the daughter is XO and her only X chromosome came from her mother, who was a carrier.
Answer:
Ossification, or osteogenesis, is the process of bone formation by osteoblasts. ... The development of bone from fibrous membranes is called intramembranous ossification; development from hyaline cartilage is called endochondral ossification. Bone growth continues until approximately age 25.
Explanation:
In prophase the chromatin condenses into chromosomes.
