5. Some snakes have hollow teeth they are called fangs that they use to poison their victim.

• Error: There is a missing comma or relative pronoun between "teeth" and "they".
• Correction: Some snakes have hollow teeth, which are called fangs that they use to poison their victims.

6. The nitrogen makes up over 78 percent of the Earth’s atmosphere, the gaseous mass surrounding the planet.

• Error: "The nitrogen" should be just "Nitrogen" because "nitrogen" is an uncountable noun and doesn't need a definite article here.
• Correction: Nitrogen makes up over 78 percent of the Earth’s atmosphere, the gaseous mass surrounding the planet.

7. Why so many students are weak at reading and math is a question continue to disturb educators.

• Error: The verb "continue" should be in the singular form "continues" to agree with the subject "a question".
• Correction: Why so many students are weak at reading and math is a question that continues to disturb educators.

8. Although apples do not grow during the cold season, apple trees must have such season to flourish.

• Error: "Such" should be replaced with "this" or "that" to make the sentence correct.
• Correction: Although apples do not grow during the cold season, apple trees must have this season to flourish.

9. Dentistry is a branch of medicine that developed very dramatically in the last twenty years.

• Error: The verb "developed" should be in the present perfect form "has developed" to match the time reference "in the last twenty years".
• Correction: Dentistry is a branch of medicine that has developed very dramatically in the last twenty years.

10. Rabbits have large front tooth, short tails, and hind legs’ feet adapted for running and jumping.

• Error: "Tooth" should be plural "teeth" since rabbits have more than one front tooth.
• Correction: Rabbits have large front teeth, short tails, and hind legs adapted for running and jumping.