Statement D. Is not true.
Myelin can greatly increase the speed of electrical impulses in neurons because it insulates the axon and assembles voltage-gated sodium channel clusters at discrete nodes along its length.so the signal speed might slow down as it got halved
Myelin is the insulating layer, or sheath that forms around the nerves, including those in the brain and in the spinal cord. It is made up of some protein and fatty substances. This myelin sheath is allows electrical impulses to the transmit quickly and efficiently along with the nerve cells. If the myelin is damaged, these impulses slow down.
Myelin is repaired or replaced by the special cells in the brain called as oligodendrocytes. These cells are made from special type of stem cell that found in the brain, called as oligodendrocyte precursor cells (OPCs).
To know more about Myelin visit:
brainly.com/question/28104242
#SPJ4
The correct answer is: In trisomy there would be one extra chromosome; in a duplication, the number of chromosomes would be normal, but one chromosome would have two copies of a portion of the chromosome.
Trisomy is a type of polysomy (chromosome aberration with extra number of chromosome/s) and also type of aneuploidy (an abnormal number of chromosomes).
Instead of the normal two (one from mother one from father) chromosomes, people with trisomy have three chromosomes. This condition occurs when chromosome pairs fail to separate properly during cell division.
Duplication, on the other hand, usually refers to a region of DNA that is being duplicated. This condition occurs as products of several types of errors in DNA replication and repair machinery.
A macrophage may engulf a pathogen by endocytosis, which involves the reorganization of actin microfilaments in the membrane and microtubules in the cytoskeleton.
<h3>What is endocytosis?</h3>
Endocytosis is a cellular process by which a cell can absorb materials from the surrounding medium, such as viruses and bacteria in the case of macrophages.
Microfilaments and microtubules are proteins that form part of the cytoskeleton and dynamic conformational changes of them are associated with the cytoskeletal rearregement during the phagocytic process.
The actin microfilaments in the membrane and microtubules in the cytoskeleton form part of the process of endocytosis because they need to reorganize during cell movement.
In conclusion, a macrophage may engulf a pathogen by endocytosis, which involves the reorganization of actin microfilaments in the membrane and microtubules in the cytoskeleton.
Learn more about actin filaments here:
brainly.com/question/13777481
#SPJ1