I need help with punctuation and
Standard American English mechanics

Comma:

→ Although she hated to be late, Janice opened the door and hurried in.

→ Carlos and Brantli studied together every evening, and they both aced the test.

→ Dear President Haverty,

Apostrophe:

→ Miguel said that the sun's rays are hottest in August.

Semi colon:

→ Sasha will not take French; will she take Spanish?

→ Beck will make the appetizers; he will also make two desserts.

Colon:

→ Please, do not be late. I expect you at 10:30a.m

Explanation:

Commas are needed when separating independent clauses  which are actually joined by: and, so, but, yet, etc. It is also used after introductory words or phrases.

The semicolon is actually used in order to link two independent clauses that are closely related in thought. Colon helps to amplify or explain further what was stated. It is used in writing time- separating hour from minute.

Apostrophe helps to show possession. It is actually used in possessive nouns.

"the day we found the sharks' teeth" i would say highlight the element of the plot as it sets its boundaries and centers the adventures of them being on a boat and cleaning spit of sand.