Mutations are spontaneous and occur at random however there are some mutagenic agents which increase the chance of this happening such as radiation exposure. If it is a point shift mutation then only a few bases on the dna sequence are changed so only changes a few of the amino acids in that chain (such as inversion of a base). If its a frame shift then the base sequence is altered so much so that every amino acid from after that changes (such as deletion of a base) which can create things such as cri-du-chat syndrome which results from a piece of chromosome 5 is missing. Hope this helps:)
We know that purebred means that the organism contains the same alleles for the trait and hybrid means that it contains two different alleles for the trait. Dominant means that it will be shown in a hybrid and a purebred, but recessive traits will only be shown in purebred recessive organisms.
a) The offspring of a purebred white (recessive) cow and a purebred brown (dominant) bull, would be all hybrid brown (dominant). This is because as I stated above, dominant traits are shown when the offspring has both dominant and recessive alleles for the same trait.
b) The offspring of a purebred brown (dominant) cow and a purebred brown (dominant) bull would all be purebred brown (dominant). This is because if both of the parents have only alleles that code for brown color, the only color that the offspring can be is brown.
c) The offspring of a purebred white (recessive) cow and a purebred white (recessive ) bull would all be purebred white (recessive), for the same reason stated above in part b), the only difference being that the alleles are recessive and code for white color instead of being dominant and coding for brown color.
d) The offspring of a hybrid brown (dominant) cow and a purebred white (recessive) bull would be half hybrid brown (dominant) and half purebred white (recessive). This can be seen best if you set up a Punnett Square, which is a diagram that shows allele frequencies in offspring. This shows you that the chance that the offspring get the dominant allele from the mother cow is 50%, thus 50% would be hybrid brown (dominant), as the father can contribute only a recessive white allele. The other 50% would be purebred white (recessive) because the mother cow would be contributing a white allele and so would the father.
Hope this helps! :)
Answer:
Index fossils
Explanation:
The index fossils are the fossils that come in very handy for the geologists when it comes to identifying or dating rock samples or other fossils. The reason for this is that the index fossils have already been dated. They are fossils that are very commonly found, wide dispersed, are easy to be identified, and are limited to only a certain geological period. These characteristics make them an excellent indicator for the dating of the rock layers in which they are found, or the fossils found in the same layers with them, without conducting further examinations.
-DNA is double stranded,RNA is one stranded
-DNA contains the following nitrogenous bases:Adeninde Guanine Timine Citozine while RNA contains Adeninde Guanine Citozine and Uracil
-DNA function is to contain the information for manufacturing proteins while there are many types of RNA with whole different jobs for example:messanger RNA(mRNA) it coppies a sequence from the DNA strand and takes it to the ribosome in order to be translated as the order for placing aminoacids in the polypeptide strand;transport RNA(tRNA) it is a short RNA strand containing up to 100 nucleotides it takes aminoacids to the ribosome so the polypeptides strand can start to be manufatured from aminoacids in an order inscripted in the mRNA.
