Answer:
True
Explanation:
Periaqueductal gray matter is found in the middle portion of brain. When this grey matter is stimulated it activates neurons that releases enkephalin. Enkephalin further direct the stimulation to the raphe nuclei with in the brain stem that releases serotonin. In this process, the ascending and descending axons are released from
a) subcortical nuclei
b) spinal trigeminal nuclei
c) the spinal cord
Hence, the given statement is true
C cause they won’t be identical to the parent since they are reproducing sexually
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.
Answer;
-A motor protein called dynein
Cilia and flagella bend because of a motor protein called dynein.
Explanation;
-Both prokaryotic and eukaryotic cells contain structures known as cilia and flagella. These extensions from the cell surface aid in cell movement. They also help to move substances around cells and direct the flow of substances along tracts.
-Cilia and flagella are formed from specialized groupings of microtubules called basal bodies. If the protrusions are short and numerous they are termed cilia. If they are longer and less numerous they are termed flagella.
