10 points and brainliest for the first to answer!
word bank:
acid, atomic number, base, buffer, chemical bond, chemical reaction, covalent bond, crystalline, hydrophilic, hydrophobic, ionic bond, isotope, matter, neutron, ph, physical property, polar molecule, proton, radical, radioactive

a(n) substance has a regularly repeating arrangement of atoms.

My question says on my assignment. read the following scenarios and decide which of the properties of life are being described. the first one is. katherine stopped on the way to school to grab some donuts. 2. because a dog cannot sweat, it has to pant in order to stay cool. 3. an elephant trun had no bone but 4,000 muscles. i have no idea what i am supposed to anwer. i can't find the answer in my notes or book that i can understand anyway

An easy way to calculate the amount of energy available at each level is to what?

What does polymerase chain reaction (pcr) do? o a. separates dna fragments by size o b. cuts a dna sample into fragments o c. provides an overall picture of a person's chromosomes o d. makes more copies of a sample of dna