When the organism become bipedal, they walk with 2 legs so there are 2 arms that were unused. Some of them try to use that hand by grabbing stick or stone, leading to tools. They start to think more to develop tools and their brain capacity become increased.
The ability to use stone tools will help in food digestion since it can break the food easier. This reduces the needs for bigger teeth/jaw.
Photoreceptor proteins are light-sensitive proteins involved in the sensing and response to light in a variety of organisms. Some examples are rhodopsin in the photoreceptor cells of the vertebrate retina,phytochrome in plants, and bacteriorhodopsin<span> and bacteriophytochromes in some bacteria.
I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!
</span>
