<span>The structure of the feet and legs varies greatly among frog species, depending in part on whether they live primarily on the ground, in water, in trees or in burrows. Frogs must be able to move quickly through their environment to catch prey and escape predators, and numerous adaptations help them to do so. Most frogs are either proficient at jumping or are descended from ancestors that were, with much of the musculoskeletal morphology modified for this purpose. The tibia, fibula, and tarsals have been fused into a single, strong bone, as have the radius and ulna in the fore limbs (which must absorb the impact on landing). The metatarsals have become elongated to add to the leg length and allow the frog to push against the ground for a longer period on take-off. The illium has elongated and formed a mobile joint with the sacrum which, in specialist jumpers such as ranids and hylids, functions as an additional limb joint to further power the leaps. The tail vertebrae have fused into a urostyle which is retracted inside the pelvis. This enables the force to be transferred from the legs to the body during a leap </span>
<span>The muscular system has been similarly modified. The hind limbs of ancestral frogs presumably contained pairs of muscles which would act in opposition (one muscle to flex the knee, a different muscle to extend it), as is seen in most other limbed animals. However, in modern frogs, almost all muscles have been modified to contribute to the action of jumping, with only a few small muscles remaining to bring the limb back to the starting position and maintain posture. The muscles have also been greatly enlarged, with the main leg muscles accounting for over 17% of the total mass of the frog.</span>
Answer:
mice and humans share virtually the same set of genes
Explanation:
Almost every gene found in one species so far has been found in a closely related form in the other. Of the approximately 4,000 genes that have been studied, less than 10 are found in one species but not in the other.
I answered it before !!
B is the correct one !! Mitosis in two identical diploid and meiosis in 4 genetically varied haploid !!
The right answer is metaphase II.
The process is performed in two nuclear and cytoplasmic divisions, called first and second meiotic division or simply meiosis I and meiosis II. Both include prophase, metaphase, anaphase, and telophase. First division prophase is long and consists of 5 stages: leptotene, zygotene, pachytene, diplotene, and diakinesis. It is at this point that genetic recombination takes place at the level of chiasmus.
During meiosis I, the members of each homologous pair of chromosomes are paired during prophase, forming bivalents. During this phase, a protein structure, called synaptonemal complex form, allows recombination between homologous chromosomes. Subsequently, a large condensation of the bivalent chromosomes occurs and go to the metaphase plate during the first metaphase, resulting in the migration of n chromosomes to each of the poles during the first anaphase. This reduction division is responsible for maintaining the number of chromosomes characteristic of each species.
In meiosis II, as in mitosis, the sister chromatids comprising each chromosome are separated and distributed between the nuclei of the daughter cells. Between these two successive steps, there is no DNA replication. The maturation of the daughter cells will result in the gametes.
