Explanation:
In the majority of cases, the extra copy of chromosome 21 comes from the mother in the egg.
In a small percentage (less than 5%) of cases, the extra copy of chromosome 21 comes from the father through the sperm.
In the remaining cases, the error occurs after fertilization, as the embryo grows.
Answer:
all functions
Explanation:
To survive, unicellular cells must carry out all functions.
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Answer is D.
Waste products from metabolism are carried by the circulation to the kidneys, which filter them out if the blood to be excreted in urine.
Answer:
Diffusion
Explanation:
Diffusion is a process of passive transport in which molecules move from an area of higher concentration to one of lower concentration.
