How do you do this i don't understand

What are the main functions of the human skeleton? a exchange of gases b support and movement c sensing the environment d digestion and excretion

Which statements describe continental crust? select the three correct answers. a-it is formed in all parts of the continents. b-it is made mostly of volcanic rock. c-it is destroyed by melting near the top of the mantle. d-it is less than 10 km thick. e-its ages ranges from very young to more than 4 billion years old.

Atotal of 980 students were asked what their favorite holiday was and 525 students said christmas what percent of students said christmas was their favorite holiday