So you know how it fits together, the ordering of the sequence.
Answer:
The temperature is staying the same. In the graph when it shows solid/liquid and liquid/gas, the temperature stays the same until it changes. This is because it reached it's melting point/vaporizing point. For example, a solid gets heated up, it then reaches it's melting point but it can't go higher than that because it isn't fully a liquid yet, once it's a liquid it will then continue to rise in temperature.
I don't think I put enough detail into that explanation but I hope this helps your problem.
Answer:
b. They cannot reproduce outside of a host cell.
Explanation:
Viruses are <em>parasitic organisms</em> that need a<em> host</em> in order to<u> thrive</u> and <u>reproduce</u>. This means that they cannot replicate outside of a host cell, but can only do this by parasitizing it. They have to find a host cell in order to continue their life-cycle or else they won't thrive. The word "obligate" means <em>being restricted to a specific mode or function in life</em>. This shows that the virus has a restriction when it comes to <u><em>reproduction.</em></u> It cannot reproduce without finding a host cell.