Answer:
Magnets come in a variety of shapes and one of the more common is the horseshoe (U) magnet. The horseshoe magnet has north and south poles just like a bar magnet but the magnet is curved so the poles lie in the same plane. The magnetic lines of force flow from pole to pole just like in the bar magnet.
Explanation:
Nuclear reactions are the reactions in which nucleus of an atom changes either by splitting or joining with the nucleus of another atom.
There are two types of nuclear reactions.
- Nuclear fission - In this process, large atomic nuclei splits into smaller nuclei.
- Nuclear fusion - In this process, two small nuclei combine together to form a large nuclei.
Both nuclear fission and fusion processes involve nuclei of atoms.
For example, 
Thus, we can conclude that statements which are true are as follows.
- Nuclear reactions involve the nuclei of atoms.
- The products of nuclear reactions are lighter than the reactants.
To test a food for starch, you can add a few droplets of iodine to it, if the liquid changes to a blue/black color then starch is present. To test for sugar you can use Benedict's solution, which will also have a color change from blue to yellow/red/orange. Add Biuret Reagent solution to test for protein, the solution will turn a pink or purple color... Note that this may not improve the taste or color of your gingerbread biscuit though :)