B. Old Stone Age.........................
The prevalence of HIV infections remained the same during the year of 1997
Organ Systems. When a group of organs work together to carry out a body function this is the what it is called.
Integumentary system. This is the external covering of our body, our skin.
Skeletal System.
Muscular System.
Nervous System.
Endocrine System.
Cardiovascular System.
Lymphatic System.
Weed, also known as marijuana or cannabis, is usually detectable in bodily fluids for 1 to 30 daysTrusted Source after last use. As with other drugs, it may be detectable in hair for several months.
Weed detection windows depend on how much you smoke or ingest, as well as how often. In general, higher doses and more frequent use are associated with longer detection times.
For daily users, cannabis may be detectable for several months after last use. The longest-reported detection times are more than 90 days.
hope it helps...!!!
Answer: 
- Lead, cobalt, arsenic and selenium appear to pass the placental barrier by a diffusion mechanism. It was also found that the mercury levels in cord blood were almost double those of the mother, suggesting that the foetus may act as a filter for the maternal mercury levels during pregnancy.
Explanation:
- Have a terrific day! <3
- Make sure to thank & rate, it’s always appreciated! <3