A/N: Wow. This story has gotten more follows/favorites than any other story I've done so far. And I'm only on the first chapter! When I read the reviews and saw how many follows/favorites I had gotten after just a few hours I had a happy heart attack! :D

The idea for this chapter is kinda what inspired me to write it. Which, considering the content, is...kinda weird.

Hayden101: Thanks for the idea for a future chapter! I hadn't thought of that 'till I read your review. That chapter is going to be very interesting. Mwa ha ha ha!

Ratchet's Sparkling: So glad you liked it! I had to look up anthropologist on Google 'cause I didn't know what it meant. :) And the award for stupidest person of the year goes to...Me! (I get that award a lot.) I love your profile pic! I have the same one for my Tumblr.

A big thank you to everyone who favorited/followed/reviewed this story! It makes me so happy when you do!

Disclaimer: I own nothing. My parents buy most of my stuff. Including the clothes I'm wearing. O_O I. Own. Nothing.

Rated T for discussion of human anatomy in some chapters.

And in case you didn't figure out from the title, this chapter talks about the human digestive system. I tried to describe the last part clinically and make it kinda vague.

Chapter 2: The digestive system

After a bout with the Decepticons, and a successful energon raid, the 'bots would have liked nothing more than to sit back, relax, and enjoy the victory. But idle hands are the devil's workshop (or playground, something like that) so Optimus and Bumblebee had gone out on patrol, and Arcee went to pick Jack up from his job. Ratchet was somewhere doing something sciency, nobody really knew exactly where, but he was in the base and that was good enough for them.

So Bulkhead, free of responsibility, was watching Raf and Miko playing video games. Miko was an expert at video games, but Raf was an expert with technology, so it was pretty close.

First Raf would take the lead, then Miko, then Raf, then Miko, then Raf, then Miko, and Raf passes her just before the finish line!

"Yes!" Raf shouted out his victory while Miko tossed her controller on the couch in defeat, followed by a pout on her face.

"You may have won this time mister, but I will be walking away the winner before we're through! But first I gotta go use the bathroom."

As she hopped off the couch and started a brisk walk toward the restroom in the back Bulkhead looked after her in confusion. "Why do you need to go there? Do you need to wash yourself?"

Miko stopped and looked at him. "Umm...no. I need to 'use the bathroom'." "I don't...What?" "Ugh, I gotta go now! Raf, you explain." Raf's head snapped up. "What? Why me?" "Because you're the only other one here who can explain it and I need to go NOW. Good luck!" She ran into the back even as Raf yelled after her.

Left alone with Bulkhead he looked at the still confused wrecker. "So, you wanna know what that was all about huh?" "Well, yeah. It must be pretty important for you to get so upset." Bulkhead replied. He was curious now and just had to know what it was that made Miko leave in such a hurry. He didn't know she wanted to wash herself so bad. Humans were very demanding at times.

"Well, not THAT important. But maybe it is time you learned of our digestive system."

Wait. What did consuming energy have to do with grooming?

Raf grabbed his laptop and after a bit of typing he showed Bulkhead a diagram of the human body. Or at least, what was inside of it.

"You see, unlike Cybertronians, humans have a much larger variety of energy sources. While you consume energon for the most part, humans can consume a large variety of foods, including meats, fish, fruits, vegetables, dairy, and a few others. There are lots of things that humans are able to eat, it's just that not all of them taste good, so humans stick with certain food that they like."

They could consume more than one thing! That makes sense, he never heard of a food war. He had heard of a 'food fight', but that was on a very small scale and didn't involve death. "Wow, so humans can eat a lot of different things? It must be easy for you to find food with so many choices."

"Yeah, I guess. But anyway, we need to eat a variety of foods so that we get the vitamins and minerals we need to function." So if they didn't eat different foods, they got sick? Maybe having one energy source wasn't so bad after all.

"So the first thing we do is, obviously, eat the food which travels down the throat into the stomach." As he explained, he pointed to the different parts of the body on the screen.

"In the stomach the food is broken down with acidic stomach juices and enzymes, then it passes into the small intestine where with the aid of the liver, gallbladder, and other organs, it takes most of the nutrients and water out of the food and sends it on to be processed further."

All this happened in their squishy bodies? Bulkhead always thought that their body just absorbed whatever they ate directly into their body. Who knew that all these 'organs' where packed in there? How did they all fit anyway?

His thoughts were interrupted when Raf continued with the explanation. "Then it passes into the large intestine where any last nutrients are extracted, and what's left is waste. The liquid waste leaves through here, and the solid, through here." He explained, pointing to the places he described.

"But that's-" "Yes, that's where the waste comes out, and that is why Miko had to use the restroom, to get rid of the waste."

Bulkhead didn't know what to think. This was pretty disgusting. Cybertronians didn't emit much waste at all since energon was pretty much pure energy. But this. This was ridiculous! And all humans functioned like this? No wonder Ratchet disliked humans, these organics were pretty gross sometimes.

Of course, that didn't mean he didn't love Miko anymore, he just needed to wrap his processor around all this.

"Uh...Thanks Raf, that was...very informative. I uh, gotta go and do...something...right away."

"Sure, Bulk." Raf knew this was a lot for the wrecker to take in and he needed some time to process this, so he let him leave without any questions.

Bulkhead got up, and with a dazed look on his face he slowly walked toward the exit, planning on going for a drive...a long drive.

Optimus chose that moment to walk in, having just returned from his patrol, and saw the look on the green mech's face. "Bulkhead? Are you alright?" "Huh? Yeah, fine boss. I just uh, have to do something...yeah." And he quickly transformed and raced out of the base.

Optimus stared after him in confusion, and then walked over to Raf. "Rafael, do you know what is troubling Bulkhead?" "Nothing really important Optimus. He just learned something about our biology." "What is it about humans that troubled him?" "Um."

Just then Miko walked in from her trip. "Hey, I'm back!...Where's Bulkhead?"

"Well... I taught him about how we digest food and he didn't take it too well."

"The last part?"

"Yup."

"Oh, I don't blame him, it is pretty weird. It happens to me and I think it's gross! Hey, Optimus! Wanna learn how we digest our food?"

"Miko!"

A/N: I hope you liked this chapter! The next one is going to be taking a break from human biology and will be exploring human culture! The subject: Games! Yes, the next chapter will be about the 'bots learning/playing human games. So if you have a game you want to see them learn, leave it in a review! I need some suggestions cause I only have a few game ideas so far.

Please leave a review and tell me what you thought of this chapter and leave any suggestions for future chapters.