1. True- because scientific theory means that <span>idea supported through research that attempts to explain existing observations or predict new ones.</span>2. False- because a cross-sectional means that its a study that is about different groups.
3. B-<span>An extraneous variable clarifies the relationship between the independent and dependent variables.</span>
Known as cumulative trauma disorders
Answer:
According to the National Center for Health Statistics, the number of overdose deaths involving opioids rose from 28,647 in 2014 to 33,091 in 2015. Heroin overdose deaths rose from 10,574 in 2014 to 12,990 in 2015, an increase of 23 percent.
Explanation:
I think you mean sperm cell. It is called fertilization.