Quick Answer. In some rare cases, excessive stress causes bleeding between periods. It is more common that another condition is responsible, such as pregnancy, polycystic ovary syndrome, infection, pelvic inflammatory disease or side effects of medication, according to WebMD.
Characteristics of Scientific Research. When researches progress to a certain degree, turning over to think about them in time will contribute to advance their process and make them develop healthily in correct direction. Therefore, let's have a look into the characteristics of our work macroscopically and generally.
Experimental and Nonexperimental Research. The basic building blocks of quantitative research are variables. Variables (something. that takes on different values or categories) are the opposite of constants (something that. cannot vary, such as a single value or category of a variable).