What prevents the expression of a recessive allele

When a comet collides with earth, it adds material to our planet and causes great damage. therefore, a collision like this is a a. destructive force b. constructive force c. geologic process and event d. constructive and destructive force

Is 9 correct? and can someone me with 10? it’s due tomorrow, you

Write a balanced equation showing the formation of copper (ii) nitrite from its elements