Sediment. So the river picks up sediment when it is moving quickly and deposits it when it slows down (or when there is a bend in the river).
B. The brain reacts to excessive dopamine levels by increasing the number of dopamine receptors.
Genes are segments of DNA located on chromosomes. A gene mutation is defined as an alteration in the sequence of nucleotides in DNA. This change can affect a single nucleotide pair or larger gene segments of a chromosome. DNA consists of a polymer of nucleotides joined together. During protein synthesis, DNA is transcribed into RNA and then translated to produce proteins. Altering nucleotide sequences most often results in nonfunctioning proteins. Mutations cause changes in the genetic code that lead to genetic variation and the potential to develop the disease. Gene mutations can be generally categorized into two types: point mutations and base-pair insertions or deletions.
They can cause Down's syndrome or some other chromosomal disorder
