<span>Isometric muscular contractions do not change the length of the muscle they are responsible for movement. Isotonic muscular contractions will lengthen or shorten the muscle. Concentric contractions shorten the muscle. Eccentric contractions lengthen the muscle.</span>
Their roots are near the surface, where they have access to oxygen.
During meiosis crossing over occurs at the pachytene stage, when homologous chromosomes are completely paired. At diplotene, when homologs separate, the sites of crossing over become visible as chiasmata, which hold the two homologs of a bivalent tighter until segregation at anaphase.
