The amount of light entering the eye is controlled by the pupil, which is surrounded by the iris.
Answer:
Atoms containing the same numbers of protons and different numbers of neutrons are <u>isotopes</u>.
Answer:
Sickle cell disease is due to a type of substitution mutation.
Explanation:
Sickle cell disease is a condition that is transmitted from parents to children in an autosomal recessive inheritance pattern. It is due to a mutation that is capable of altering the shape of the erythrocyte, as well as its ability to circulate and carry oxygen.
The mutation that occurs in sickle cell disease is due to an alteration in the β-chain of hemoglobin, caused by the substitution of thymine base by adenine in the DNA that determines it. As a result, valine replaces glutamic acid in the β-chain amino acid sequence, with the consequences described.
- <em>The other options are not correct because </em><u><em>deletion, duplication and translocation </em></u><em>correspond to chromosomal mutations, not responsible for sickle cell disease.</em>
