A gateway substance is something that may be menial but could lead to something bigger, an example is weed in the drugs world, weed is not hard to get and is usually a gateway drug to stronger types of drugs and potentially more dangerous
Answer:
gas, liquid & a solid
Explanation:
carbon dioxide, sweat/pee
Answer:
An intrauterine device, also known as intrauterine contraceptive device or coil, is a small, often T-shaped birth control device that is inserted into the uterus to prevent pregnancy. IUDs are one form of long-acting reversible birth control.
Answer:

Exocytosis is the reverse of endocytosis. <em><u>Quatities of material are expelled from the cell without ever passing through the membrane as individual molecules.</u></em> By using the processes of endocytosis and exocytosis, some specialized types of cells move large amounts of bulk material into and out of themselves.
Answer:
The correct answer is - 0 m/s.
Explanation:
In this position-time graph or distance-time graph, there are three different part that shows three different velocities one in increasing as it moves from a lower position in relative to time and one is stationary and the third is decreasing.
'Straight lines' on a distance-time graph suggest that the movement of the object is constant. During 'Part B' of the journey the object travels 0m in 3s. It is stationary for 3 seconds so the velocity will be zero as well.