The correct answer is option B, that is, covalent bonds.
Covalent bonds are more prevalent in organic chemistry in comparison to ionic bonds. A covalent bond comprises of the concurrent attraction of two nuclei for one or more electron pairs. The electrons situated between the two nuclei are known as bonding electrons.
Covalent bonds take place between different atoms or similar atoms whose difference in electronegativity is not enough to permit the transfer of electrons to produce ions. The covalent bond is demonstrated by either as a solid line or long dash or as a pair of dots.
Answers:
- The sequence encodes a gene that is critical for life and cannot be easily mutated while retaining function.
- The sequence is contained in a retrovirus that has infected both species.
1- Explanation:
6.8 million years is a considerable period of time and if the cats were evolved in two different specie then technically they should have substantially different sequences of gene. However, there are some genes that are critical for the survival of the organisms because they encode a function which is equally important for the organisms of a certain category, even if they are different specie.
For example, the essential genes that are involved in maintenance of metabolism, initiation of replication or translation of genes. Therefore, with the period of time, the mutation of even a single nucleotide can be lethal for these genes, and if it happens organism will simply die. So, if one organisms is died that cannot take part in the process of evolution and would clearly be cut off from the process, However, those who survive can undergo some other mutations and become separate specie.
2- Explanation:
A retro virus inserts itself in to the genome of host organisms and become a part of them. It is very difficult to detect the presence of the retro virus until the organism undergoes infection due to its attack. Cats are a favorable host for retroviruses - called lentiviruses which attack the cats to cause a critical syndrome Feline Immunodeficiency Virus or FIV. Therefore, it is possible that same retrovirus having a particular sequence has attacked both cats and the sequences were taken from those cats.
Hope it help!
Since the male and the female have recessive alleles of this gene, all of their offspring will be like that too.
rr x rr cross will result in 100% of the offspring with the genotype: rr
R- dominant (but none of the parents has this allele)
r- recessive
