Placenta
It also does not allow the maternal and fetal bloodstreams to mix
Streams or rivers form when water that does not find an underground aquifer, drains off the land by either seeping through the soil or spilling over the surface into the river or stream bed.
Answer:
1. Both Hydrogen should be positive and Oxygen is negative. I can't tell which photo that would represent however my best guess would be #2.
2. D
3. A
