Answer:
A and C
Explanation:
X-linked recessive diseases are disorders caused by a mutation on the X chromosome causes the phenotypic expression in males and only when it is homozygous for females.
A small percentage of women can display the disease phenotype on rare phenomenon such as;
- X-inactivation that favors inactivation of the normal X chromosome
- Turner syndrome (a sex-chromosome aneuploidy in which women have only one X chromosome)
Speciation! Speciation occurs when a single species becomes two or more separate populations by a geographical barrier. This changes each population’s environment which forces them to adapt. Eventually these populations will become so different from each other that they will not be able to interbreed populations and create fertile offspring. This is what makes them different species, but they still share a common ancestor.
The answer: ribonucleic acid (RNA)
Explanation: RNA was the first molecule of heredity, so it evolved all the essential methods for storing and expressing genetic information before DNA came into the scene.
Answer: Where would the blood come from if there were a blockage just posterior to the middle cerebral artery on the left? If blood could not get to the middle cerebral artery through the posterior circulation, the blood would flow around the circle of Willis to reach that artery from an anterior vessel.
Explanation: