For natural selection to happen <span>there must be genetic variation in the population for it to even work</span>
Quite simple really.... The CNS actually doesn't receive as much nutrients or key components from the blood... The blood actually dumps it into the Cerebrospinal fluid. The Cerebrospinal fluid therefore is directly in contact with the brain and if you want to find an infection you take from a source as close to thing as you can.
Answer:
A) missing one X chromosome
B) XXY
C) extra 21 chromosome
D) all relevant number of chromosomes
Explanation:
A) See attachment 1
B) see 2nd attachment
C) see 3rd attachment
D) see 4th attachment
Answer:
Endoplasmic reticulum and ribosome!
Explanation: