Answer:
Answer is C.
Explanation:
For A and B, a base substitution affects one of the three bases that comprise a codon, the DNA/RNA unit that corresponds to a particular amino acid. If one base is substituted, one codon and therefore one amino acid will be affected. Codons have built-in redundancy, so even by changing one base, the new codon sometimes still corresponds to the same amino acid. Therefore, a base substitution at most affects one amino acid, and sometimes doesn't affect it all.
Frameshift mutations cause a lot more trouble. These occur when you have a deletion or insertion that changes the number of bases in your gene. As a result, the "frame" of the codons changes (everything shifts one way or the other by the number of bases added/removed). This affects EVERY codon downstream of the mutation, so you can imagine that such a mutation would have a bigger effect the closer to the start of the gene it occurs. This is why C is correct.
Answer:
1. Arsenic, benzene, formaldehyde, lead, and mercury are just a few of the more than 70 cancer-causing chemicals in cigarette smoke.
2.They work, for instance, to keep the airways clear of mucus and dirt, allowing us to breathe easily and without irritation. They also help propel sperm.
3.Spirometry measures how much air you can breathe in and out. It also measures how fast you can empty the air out of your lungs. Spirometry helps diagnose breathing problems such as asthma and COPD.
4.
Tar causes cancer of the lungs, mouth and throat.
When speaking about pre-molars, we would only contain 8 pre-molars, and this is due because we only contain 32 teeth.
We have : (8 pre-molars)
We have : (12 molars)
We have : (8 incisors)
And for the last part, we would contain : (4 canines).
Explanation:
Many scientists believe that RNA, or something similar to RNA, was the first molecule on Earth to self-replicate and begin the process of evolution that led to more advanced forms of life, including human beings.
The main causes of climate change are: Humanity's increased use of fossil fuels – such as coal, oil and gas to generate electricity, run cars and other forms of transport, and power manufacturing and industry. Deforestation
Volcanologists can predict eruptions—if they have a thorough understanding of a volcano's eruptive history, if they can install the proper instrumentation on a volcano well in advance of an eruption, and if they can continuously monitor and adequately interpret data coming from that equipment.