1.

1. Wrong: ‘its’ – pronoun agreement error
2. Wrong: ‘and’ – wrong usage of and
3. Wrong: naming – wrong usage of past continuous
4. Correct: them, their – agrees with mountains
5. Wrong: ‘it’ - pronoun agreement error

2.

1. Wrong: dangling modifier –subject ‘it’ is required
2. Wrong: same as A
3. Wrong: same as A
4. Wrong: split infinitive – to seriously study
5. Correct: “it was not until almost’ correct modification