The challenges that scientists who want to study particular genes face are as follows:
1. There are many genes on a typical chromosome - A chromosome<span> typically contains hundreds to thousands of </span><span>genes.
2. </span>A small fraction of each chromosome encodes genes - <span> Genes only make up a small percentage of the genome; the rest is composed of non-coding sequences.
3. </span>It is difficult to distinguish between genes and non-coding genetic information - discriminating between<span> coding and </span>noncoding<span> regions in a given nonannotated genomic sequence is quite difficult.</span>
Scientists will look for evidence like similar body or skeleton structures, internal similarities or maybe sometimes the whole heirarchy to confirm that two speices are closely related to each other.
For example ; in birds, scientists will look for type of feathers, body structure, beaks to confirm the similarity of two birds.
...........The answer is A
Answer:
Earth is the third planet from the Sun at a distance of about 93 million miles (150 million km).
