What makes it difficult for a vehicles driver to judge a motercyles speed and distance?

Awell-diversified portfolio needs about 20-25 stocks from different categories is this true or false?

Linux is distributed under gnu gpl. why is this important? a. it ensures that only torvalds can profit from the sale of linux b. it prevents unknowledgeable users from downloading programs they don't know how to operate. c. it provides protection for the developers who created linux. d. it states that anyone can copy, modify, and share the program if changes are made public.

An atom's diameter is about 0.1 nanometer (1×10-9m), and a human hair is about 1×10-3m. how many times greater is a human hair than an atom's diameter? sorry pushed wronf button but this is math