Yes you can have a heart attack without knowing it.
Where you the one asking about the virus ?
Answer:
Oxygen is a chemical element that constitutes 21 percent of the Earth's atmosphere, that is capable of combining with all elements except some noble gases, that is active in physiological processes of almost all known organisms, and that is involved especially in combustion — see Chemical Elements Table.
Explanation:
hope it helps
good day (≧▽≦)
Answer:
False
Nerves are kinda like the power lines for the body.
They connect to the brain and extend throughout your body and when the brain sends messages for you to move your arm the nerves help you do that. they also are how you feel. Like if you get pinched then your nerves send a message to your brain and then you realized that it hurt