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.
Humans are warm blooded and can't be cold blooded because of the environment we live in. We can't sit still during the winter and soak up warmth from the sun.
Answer:
d.They prevent the two parental strands from coming together again.
Explanation:
During the process of DNA replication, the two DNA strands should be separated from each other to serve as a template. To separate the two DNA strands, the helicase enzyme breaks down the hydrogen bonds between the complementary base pairs of the DNA strands. The process uses ATP as a source of energy.
Due to the presence of complementary base pairs, the separated DNA strands have a tendency to reanneal by the formation of hydrogen bonds. To prevent the reannealing of separated DNA strands, single stranded binding proteins bind to them. Binding to single stranded binding proteins to the separated DNA strands does not allow them to reanneal.
Three types of axonometric projection<span> are </span>isometric projection, trimetric projection. and dimetric projection.
The answer is Vascular tissue
