Strongest evidence points towards shared taxon
Microfilaments
Microfilaments are fine, thread-like protein fibers, 3-6 nm in diameter. They are composed predominantly of a contractile protein called actin, which is the most abundant cellular protein. Microfilaments' association with the protein myosin is responsible for muscle contraction. Microfilaments can also carry out cellular movements including gliding, contraction, and cytokinesis.
Microtubules
Microtubules are cylindrical tubes, 20-25 nm in diameter. They are composed of subunits of the protein tubulin--these subunits are termed alpha and beta. Microtubules act as a scaffold to determine cell shape, and provide a set of "tracks" for cell organelles and vesicles to move on. Microtubules also form the spindle fibers for separating chromosomes during mitosis. When arranged in geometric patterns inside flagella and cilia, they are used for locomotion.
Hope this helps :)
Plants get the carbon dioxide they need from the air through their leaves. It moves by diffusion through small holes in the underside of the leaf called stomata. These let carbon dioxide reach the other cells in the leaf, and also let the oxygen produced in photosynthesis leave the leaf easily.
Answer:
The correct answer is option C, that is, in the mother in meiosis II.
Explanation:
A nondisjunction in meiosis I produce all the aneuploid gametes, while nondisjunction at meiosis II produces 50 percent aneuploid gametes and the 50 percent normal gametes comprising haploid number of chromosomes.
As it is mentioned that one of the brothers possess normal number of chromosomes (46), the mother encounters nondisjunction at meiosis II resulting in the formation of one n+1 gamete exhibiting two copies of X chromosome. Fertilization of this n+1 gamete with sperm results in the creation of zygote (47, XXY).
