The point where chromosomes cross over and exchange dna during meiosis is called the

Your answer is prophase 1.

Prophase 1 is seen as the beginning of meiosis. In this step, duplicated chromosomes condense (from DNA duplication previously), homologs loosely pair along their lengths, and homologous chromatids exchange genetic material (this is what you are describing). The nucleus also disappears, and a spindle forms.

Hope this helps!

trachea, alveoli, lung capillaries, arteries

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.