the quest for civic virtue
Explanation:
improving schools, the society....to help educators like yourself, the bill of rights institute has written a New classroom-friendly curriculum called Heroes and Villains....
It has changed because earlier in the days people couldn't even figure out if the world was flat or round but now we can add decimals and multiply fractions.
penguins! so momentum is based on mass and velocity, the advantages is that they have stored mass in the form of like fats to keep them warm however they are built to slide basically so that there is less friction when they travel so sideways their bullet like shape helps increase velocity so they have both mass and considerable velocity!
Lead-207 can change into Lead-208.
When Lead-207 is bombarded with neutrons, the atom acquires the neutron. Adding a neutron only changes the mass number of the atom. This does not involve change in the identity of the atom. So, Lead-207 can change into Lead-208 without change in its chemical properties.