For the first one the answer is B. and the second one is D.
Change in velocity over time is acceleration.
You're finding acceleration .
Close all network ports, filter those you can't block
Firewalls are used to filter network traffic and are available as standard system software on most operating systems. Limit the openings hackers have to your server.
Answer: The answer for this is Compound.
Explanation: A matter is something which occupies space and has some mass.
Elements are defined as the smallest substances which cannot be broken down into another substance by any chemical means.
A compound is a defined as a substance composed of two or more different elements when they combine chemically in definite proportion. For example:
is named as carbon dioxide and is a compound made by combining carbon and oxygen in a fixed ratio of 1 : 2
So, the answer to the given question is compound.