Answer:
Apostrophe
Explanation:
The persona is directing the words to someone who appears to be in his presence
"...which you were probably..."
The speaker is addressing an absent or imaginary person that the reader cannot see but he can see or pretend to see
Answer: mass can never be created or destroyed
Explanation:
Answer:
salt crystal
Explanation:
It can dry on you and your equipment leaving crystals that might not do you much harm (dry skin, uncomfortable itchy feeling) but will definitely start degrading your equipment
Answer:
Hello sir/madam. I am requesting you to take consideration into my leaving for one day. I actually have to attend a family event and I will not be able to attend class. Please take this into consideration.

2. Although I don't like vegetables, I eat them everyday.
3. Even though she's intelligent, she gets poor marks.
4. It's hard to hike up that big hill however you'll love the view up there.
Hope this helps!