Answer:
<h2>A</h2>
Explanation:
1. Sickle cell anemia is an inherited condition, disorder (disease).
2. It is a recessive condition, in which red blood cell become mutated and converted to a sickle like shape, and there aren't enough healthy red blood cells to carry oxygen throughout the body.
3. This condition normally occur when, there is inheritance of two abnormal or mutated copies of the β-globin gene, one allele from each parent.
4. β-globin gene makes haemoglobin.
5. Sickle cell anemia results when glutamic acid being substituted by valine at position 6 ( in short E6V substitution).
6. So, it a single base-pair substitution in the gene encoding the beta subunit.
<span>an atom with a single electron in its outermost shell</span>
Answer:
In 1951 Franklin joined the Biophysical Laboratory at King’s College, London, as a research fellow. There she applied X-ray diffraction methods to the study of DNA. When she began her research at King’s College, very little was known about the chemical makeup or structure of DNA. However, she soon discovered the density of DNA and, more importantly, established that the molecule existed in a helical conformation. Her work to make clearer X-ray patterns of DNA molecules laid the foundation for James Watson and Francis Crick to suggest in 1953 that the structure of DNA is a double-helix polymer, a spiral consisting of two DNA strands wound around each other.
A scientific theory is a broad explanation for events that is widely accepted as true. Evolution is a change in species over time. Evolution occurs by natural selection. The cell theory states that all living things are made up of cells, and living cells always come from other living cells.
