Answer:
3. An even number of chromosomes are required for synapsis during prophase I and proper pairing during metaphase
Explanation:
Mules are hybrids of a cross between a female horse and a male donkey. Horses contain 64 chromosomes while donkeys contain 63 chromosomes in their somatic cells respectively. This means that they each produce 32 and 31 chromosomes respectively during meiosis. A mule, hence, contains 32+31= 63 chromosomes in their somatic cells.
This chromosome number in mules are uneven for meiosis to occur because meiotic division requires that an even number of homologous chromosomes pair together in a process called SYNAPSIS during prophase I of meiosis I. This is impossible in a mule because of the uneven number of chromosomes in its cells.
Also, during metaphase of meiosis, the homologous chromosomes need to be properly aligned at the equator for separation to occur. This is also impossible in a mule considering the number of chromosomes that don't add up.
Due to this reason of unevenness in the number of chromosomes present in a mule, meiosis will not occur and if meiosis (gamete formation) does not occur, reproduction cannot take place. Therefore, the mule is a sterile species i.e. cannot produce offsprings via sexual reproduction.
Answer:
Many people with blood cancers, such as leukemia and lymphoma, sickle cell anemia, and other life-threatening diseases, rely on bone marrow or cord blood transplants to survive.
Healthy bone marrow and blood cells are needed in order to live. When disease affects bone marrow so that it can no longer function effectively, a marrow or cord blood transplant could be the best treatment option; for some patients it is the only potential cure.
Explanation:
Yeast lacks a membrane-bound nucleus. The onion skin cell has one
7 m/s
Explanation:
Acceleration,
Where v and u are the final and initial velocities of the Justine respectively, t is the time taken for Justin to attain final velocity.
Making v the subject then
v=at+u
Taking u as zero then
Substituting 3.5 for t, 2 as a then
v=3.5*2=7 m/s
Pretty sure it's D. Mercury
