Answer:
Similarities in embryos are evidence of common ancestry. All vertebrate embryos, for example, have gill slits and tails. Most vertebrates, except for fish, lose their gill slits by adulthood.
Explanation:
itz from gologolo lol I hope it helps uh
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B)<span>When you listen to the heart sounds, you are hearing the flow of blood which stops abruptly when a heart valve closes. This produces the "lub-dub" sounds. 1st heart sound (when the Mitral Valve closes) as the ventricle contracts (systole) and then 2nd heart sound (when the Aortic Valve closes) and the ventricle starts to fill again (diastole)
</span><span>The pulse is the wave of pressure you can feel through the artery walls. This denotes systole.
</span><span>The ECG's QRS complex is the electrical signal that tells the Ventricles to contract. You can see that the QRS occurs right at the beginning of systole and triggers Isovolumetric contraction.
</span><span>So the QRS on the ECG, the pulse wave you can feel (ie. the rise in aortic pressure) and the 1st heart sound all signify SYSTOLE.
</span><span>there a delay between systole of the ECG and the resulting pulse felt in the finger (R-Pulse) </span>because it takes a little bit of time for the pressure to transmit through the body, as the finger is not on the heart (if it was there would be no delay)
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.
The correct answer is <span>(AVNRT) </span>
