The main reason is because they are heavy, and because they don't have to chase their food. They're not predators and their shells give them protection like running away gives protection to other herbivores.
Answer: The correct answer for the fill in the blank is Asexually.
Asexually reproducing organisms have rapid rate of reproduction as only a single parent is involved in this. Also, there is no formation and fusion of gametes in this mode of reproduction.
They produce larger number of offsprings through rapid rate of reproduction. By doing so they have larger chances of survival.
For instance, if a part of bacterial species population is wiped out through viral infection, bacteria can compensate this loss by the rapid rate of reproduction. This increases their chances of survival.
Carbon forms Covalent Bonds.
He wanted to see how different traits passed through the pea plants he grew. To do this, he needed to cross polliante so that their were multiple parents affecting the genes of the new pea plant. If he self pollinated, all the new baby pea plants would Look the same as their parents and we wouldn't know as much as we do about genetics now
