I believe it is D, the reason being is because they form on their own, not from a living or dead organism. It can't be B because that is true, and the same for C. hope this helps, have an amazing day :)
they contain half of a set of chromosome...that's jot true
The safety procedural step that must always be performed
when setting up a vacuum filtration apparatus is that first, you should always
wear the proper protective equipment, next is that the vacuum filtration—you should
clamp the flask of which is needed, securely to the ring stand. It must be
secure or it may be in the way of performing the experiment.