Molecular biology is a field of biology that looks at the molecular machinery of life. The field was founded in the early 1930s, though the phrase was only used in 1938 and the field didn't take off until the late 50s and early 60s. Since then, progress in the field has been massive.
The Ionosphere and the Exosphere (minor layers) are parts of the Thermosphere (major layer). The ionosphere is part of the theremosphere.
tunica vaginalis testis has two layers: visceral and parietal; the visceral layer lies on the anterolateral surface of the testis and epididymis; the parietal layer lines the inner surface of the scrotal sac; the word vaginalis is derived from the Latin word for sheath.