Scientists believe that ancient ancestors of all animals were single celled eukaryotes that sometimes grew in colonies. The correct option among all the options that are given in the question is the second option or option "B".
The Cambrian Explosion resulted in the evolution of the first representatives of most animal phyla. The correct option among all the options that are given in the question is option "B".
Atoms are the smallest building blocks of elements having the same chemical and physical properties of that specific element. Atoms combine together with the help of electrons, to form a little more complex entity like the molecules, crystals, liquids etc. Some molecules combine together to form a more complex entity like the DNA which is the most complex molecule. The whole universe is made out of these simple building blocks, including the human body.
The reaction of sodium bicarbonate (baking soda) and acetic acid (vinegar) produces carbon dioxide gas, water and sodium acetate (soluble in water). The carbon dioxide gas can originally be seen as bubbles in the solution, but will quickly be released from the solution.