Vì sao biến dị và di truyền học là hai hiện tượng song song gắn liền với quá trình sinh sản ?

adolescence is the period ................................... child and young adulthood

huy got a bad mark for his english test he must hve been really ........................

A disappointed B relaxing C interested D happy

my grandfather has devoted himself to many .......................... events in our community ( culture )

you should try looking for his telephone number on the company

in a message board you can .... messages or post questions

as soon as he will come back from his coffee tell him to see me

My mother wants me (post) ... this letter before afternoon

There /be/many/ cause/ that /lead /water pollution / Viet Nam. One / main causes /be/ waste water/ come /many factories / then being /directly/ pull/ out/ rivers, lakes or seas without any treatment because this /be/ most convenient way / dump/ waste water. Industrial waste /consist/ some kind / chemical substance which /be harmful / our life. Another cause / water pollution/ be/ lack /awareness / citizens. Every day/ people generate / lot / garbage / they throw /directly / rivers, ponds / so on.