true
Explanation:
this is because melting point and boiling point decreases down the group because they are held together by attractions between positive nuclei and delocalised electrons
The category of galaxy which does not have a distinctive shape is D. an irregular galaxy.
A spiral galaxy has a spiral shape, an elliptical galaxy has an elliptical shape, and a barred-spiral galaxy has a barred-spiral shape. The only galaxy type which does not have a constant shape is an irregular galaxy.
The physical changes are you are breaking down the food u eat and the chemical changes are when the enzymes in your stomach break down the food that you have already eaten
efficiency=work output/work input×100
since it exhausts(use up)3000j of heat that's the work input and the 1500j is the work input
efficiency=1500/3000×100
=50%
