Answer:
a nucleus of Deuterium (2H)
Explanation:
formed from two protons with the emission of an antielectron and a neutrino. In the basic Hydrogen fusion cycle, four Hydrogen nuclei (protons) come together to make a Helium nucleus.
Answer:
Elastic collisions are collisions in which both momentum and kinetic energy are conserved. The total system kinetic energy before the collision equals the total system kinetic energy after the collision. In the collision between the two cars, total system momentum is conserved.
A division of order sharing a more specific common attribute. For example, there is a Family of frogs called "Ranidae" More specifically the definition of an order is.
Gradually as the result of many intermediate steps is my answer because as life on Earth for example started off with simple atoms making molecules, and as the time went past more complex compounds were be produced. And from there later on unicellular organisms started appearing. Nothing in evolution that I know of happens in a short time, at least from the human perspective.
Vaccine, bacteria, pathogens, cells, toxins, antibiotics. In that order vaccine being first