Oparin-Haldane hypothesis. The Oparin-Haldane hypothesis is named after the two scientists; <span>Russian scientist Aleksandr Oparin and English scientist J. B. S. Haldane. The two scientists separately hypothesized that life began when some inorganic molecules were converted into organic molecules specifically amino acids by the help of energy came from a lightning struck.</span>
When referring to knowing where to find something when you need it you mean that you do not need a memorization of all things, you just need a source to find it when in need. I hope this answer suited your needs.
Answer:
No, they do not have backbones
Explanation:
When a muscle receives nerve signal contracts and pulls on a tendon.
