On average among OECD countries, there are about 14 students. per teacher at the secondary level (Table D2.2). As the differences in student-teacher ratios indicate, there are fewer full-time equivalent students per full-. time equivalent teachers at the secondary level than at the primary level of education.
Causes of Lower Back Pain. Home/Conditions/Causes of Lower Back Pain. Pain in the lower back has a multitude of causes. The discs, facets, pars interarticularis, sacroiliac joints, hip joints and nerves can all cause a form of lower back pain.
Any one of these can cause pain in your lower back. Kidney infections can also cause your back to feel the brunt. Other issues: Low back pain can also happen because of things like: Kidney stones. Endometriosis, a buildup of uterine tissue outside the uterus. Fibromyalgia, a condition that causes widespread muscle pain.