1 If the black lines aren't visible on the external screen, the laptop screen may need to be replaced. 2  If the black lines are also visible on the external screen, the video card or motherboard may need to be replaced. 3  In some cases, a loose video card can cause problems with the monitor video.
1. segmentation - (embryology) the repeated division of a fertilised ovum. cleavage. embryology-the branch of biology that studies the formation and early development of living organisms. cell division, cellular division-the process in reproduction and growth by which a cell divides to form daughter cells.
From Wikipedia, the free encyclopedia. For other uses, see Fixation. In population genetics, fixation is the change in a gene pool from a situation where there exists at least two variants of a particular gene (allele) to a situation where only one of the alleles remains.ixation can refer to a gene in general or particular nucleotide position in the DNA chain (locus). In the process of substitution, a previously non-existent allele arises by mutation and undergoes fixation by spreading through the population by random genetic drift and/or positive selection.