Answer: The right answer is Cave-ins.
Explanation: Excavations and trenches are basically the man-made cuts inside the Earth's surface. These are made for multiple purposes such as mining or tunneling. One of the obvious risk while working in such excavations and trenches is cave-ins. It is basically collapse of that excavation or Trench. The roof of the mine collapses and people working under it get buried inside those excavations in trenches.
T cells attack antigens on foreign substances and B cells produce antibodies.
There are obviously A LOT of them. Like how your brain is slowly deteriorating, which is scary and dangerous. I can't cover everything but I have a website link you could visit that talks about this subject
https://www.drugabuse.gov/publications/research-reports/heroin/what-are-long-term-effects-heroin-use
I think you didn’t finish inputting the question? If you did, I don’t understand it.