They can have a close similar appearance to the parents, have close relation of child reactions.
for example, everyone born in my father's side of the family had the tendency to bump their head on something as they fall asleep up to the point when you are a toddler.
Answer:
tan is 15 for that triangle
I can think of two of them:
-- carbon monoxide
-- black soot
Answer:2155 J
Explanation:
Given
Change in Internal energy
i.e. decrease in Internal Energy
Heat added to system 
According First law for a system



Thus 2155 J of work is done by system