Trong phòng thí nghiệm, người ta điều chế oxi bằng cách 

A. điện phân nước

B. nhiệt phân Cu(NO₃)₂

C. Nhiệt phân KClO₃ có xúc tác MnO₂

D. chưng cất phân đoạn không khí lỏng

bạn zô đây tham khảo nhé

https://hoc24.vn/hoi-dap/question/221091.html. Câu trả lời của Doraemo nha

ko thay đổi dc đâu bn ak. nếu mún thay đổi thì phải đăng kí lại thôi

3-D

2-C

1-B

5-A

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Today many species of plants and animals are in _________of extinction.

A. danger 

B. endangered 

C. endanger

D. dangerous

Hello, everybody, my name is Mai. I’m twelve years old. I study at secondary school. The name of my school is Quang Tien. I often call Quang Tien Secondary School is my second home. It is a very famous school in Thai Hoa. I will tell you about my school

Quang Tien is not very large but very spacious and clean. The school gate look like security man. School entrance is beautiful and spacious,the two sides is the flower corridor leads straight to the playground and the classrooms

School ground are not wide, Around the yard are rows of Bang trees and lawns green. After the hard classes, we usually sit in the benches, under the shade of Bang trees. The classrooms are full of tables and chairs, cabinets for learning. Besides, you also have the other classrooms as music room, computer science, library, classrooms English. In addition, there are a lot of good students and experienced teachers working there. All of them are friendly and nice. The teachers is always willing to help their students.

I even loved the school because here we have good friends and the teachers are always interested to teach and impart knowledge to us. I loved my second home!