By process of elimination you can find the right answer. We know for a fact that carbon is found in all living organisms. That is why we talk about carbon based life forms. So the first statement cannot be true. You can figure out how many Valence electrons an element has by looking at the group number. The group number of carbon is 4 so the 2nd statement cannot be true. We know that carbon does bond with other elements because it is not a noble gas and therefore must be able to form compounds.
This means the answer must be they can form up to four covalent bonds
I can certainly see how this is likely to be a science book. With the latest photographic technology scientists have photographed everything from star nebulas, space gases, to exoskeletons of creatures, flowers, sun flares, waves in motion, inside cells, etc. so yes absolutely!
Answer:
Aluminum
Explanation:
The density of Aluminum is 2.7 g/cm3
We know the volume and mass of the unknown metal, as density is mass/volume: 81g/30cm3 = 2.7 g/cm3 which is the density of Aluminum :)
Answer:
Thymidine dimers is likely to be repair as soon as it is originated but if left unrepaired then it causes frame shift mutations.
Explanation:
In case of Bacterium if UV irradiation induces covalent linkage of two thymidine present adjacently to each other or on a single strand to make thymidine dimers.
These either excised via DNA repair enzyme like Endonuclease V and the proof reading activity of DNA polymerase I enzyme help in incorporation of nucleotide by taking the unmutated original strand as a template.
These dimers if not excised before second round of replication than the sequence of newly synthesized strand will be altered. As DNA polymerase III enzyme read thymidine dimers as single thymidine nucleotide and incorporate only 1 adenine in the newly synthesizing complementary strand which results in frame shift mutations
It is the mutation in which reading frame of codons is shifted or altered due to deletion or addition of a single nucleotide.
