Describe the events that might occur if there isn’t new crust formed.

Oceanic crust is constantly formed at mid-ocean ridges, where tectonic plates are tearing apart from each other. As magma that wells up from these rifts in Earth's surface cools, it becomes young oceanic crust. ... Just as oceanic crust is formed at mid-ocean ridges, it is destroyed in subduction zones.

Explanation:

During meiosis I,the sister chromatids are still attached at the centromere. In Anaphase I of meiosis I, the homologous chromosomes break their connections and separate out. The process of separation is called  disjunction (dis-separate, junction-union). The separated chromosomes are called dyads (Gk. dyas-two) because each of them consists of two chromatids.

During anaphase II of meiosis II, the two chromatids of a chromosome separate completely forming the daughter chromosomes. At the end of anaphase II, four groups of chromosomes are produced, each group having haploid number.