~Hello there! ^_^
Your question: What subatomic particle(s) has a mass of 1 AMU?
Your answer: Both proton and electron have the same mass of 1 AMU.
Hope this helps~
It would be lithium and nickel due to the electrons
Answer: Possession of Valves
Explanation: Veins possess valves which ensures that blood flows in only one direction. Valves helps blood to flow back to the heart against gravitational force.
Arteries don't have valves because the pressure originating from the heart is capable of causing the blood to flow in one direction.
I’m pretty sure it’s species :)