Mass Effect is a science fiction media franchise created by Preston Watamaniuk, Drew Karpyshyn and Casey Hudson and owned by Electronic Arts. The Mass Effect original trilogy takes place in a fictional version of the Milky Way towards the end of the 22nd century. In 2148, humanity discovered an alien outpost on Mars, and learn that Charon is actually an alien artifact known as a "mass relay" that enables faster-than-light travel to other mass relays located across the galaxy. Humanity comes into contact with numerous other space-faring alien species, some far more advanced than humans. The center of the Council's governing power is the Citadel, another artifact and a massive space station that, like the mass relays, were made by a race known as the Protheans believed to be the progenitor race for all species but long since disappeared. Over the next few decades, humanity is given access to new technology, allowing them to colonize new planets, and they are made part of the Citadel Security (C-Sec) forces, a highly regarded position that other species had been long waiting for and take resentment over.

While various features of gameplay varied across the series, the Mass Effect games are action role-playing games. The player customizes their version of the game's main character (Shepard for the first three games, and Ryder for Mass Effect: Andromeda) based on physical appearance, background, and one of six character classes, each class centered around one or two specializations in combat, technology, or "biotic" (magic-like) skills. This establishes a skill tree that the player can advance through as their character gains experience levels through completing missions. Each game generally follows a main story pathway with points of branching narratives and multiple side missions, allowing the player to proceed through the game as they desire. Both story and optional mission most often involve using their ship to travel via the mass relay to remote star systems and explore planets to find target objectives. When exploring planets, the player has the option to bring up to two of their crew members with them, who generally act autonomously but can be given specific orders by the player. In missions, the player can explore an area to find information, discover lootable objects with new gear or in-game currency, non-playable characters to talk to, and key mission items that are to be recovered. Frequently, the player will enter combat, which plays out as a third-person shooter, with the player and their allies using a combination of their weapons and combat, tech, and biotic powers along with tactic use of the environment to defeat opponents.

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Milky Way
Asari	Batarian	Drell	Elcor	Geth	Hanar	Human	Krogan	Leviathan	Prothean	Salarian	Turian	Volus
Milky Way			Andromeda
Vorcha	Quarian	Yahg	Angara	Kett

Each class has distinct proficiencies in three main areas: general combat using firearms or melee strikes, tech attacks, and biotics. Classes can be further specialized to have even more intense focuses or proficiencies. Explorer is unique to Andromeda.

		Class	Type	Description	Specializations
		Adept	Biotic	M1: The ultimate biotic, able to affect the physical world with the power of the mind. Gameplay focus is on disabling and debuffing enemies while dealing massive amounts of damage. M2 / M3: Adepts are biotic specialists, capable of disabling and killing enemies with raw biotic power. While they lack advanced combat training, they are the best at defeating enemies without firing a shot.	Bastion Nemesis
		Soldier	Combat	M1: A tough warrior, able to deal with a range of combat situations. The Soldier gets improved health, has the widest selection of weapons, and is eventually able to wear heavy armor. Gameplay focus is on getting into the thick of the fight, picking the right weapon for tactical situations, and outlasting opponents. M2 / M3: Soldiers are pure combat specialists. No one is tougher or more effective at taking down enemies with gunfire. Soldiers have the most thorough weapons training and can use all special ammo types.	Commando Shock Trooper
		Engineer	Tech	M1: A tech specialist, able to quickly and easily manipulate the environment with specific talents, and repair or modify technical equipment. Gameplay focus is on shaping the battlefield during combat, healing the party, and debuffing enemies. M2: Engineers are tech specialists, the only class able to employ combat drones on the battlefield. Engineers are the most effective class at blasting through enemy defenses and disabling opponents. M3: Engineers are tech specialists, the most effective class at disabling the defense of the toughest enemies or incapacitating them to render them harmless. In combination with their weapons training, Engineers have the unique ability to spawn combat drones that can harass enemies or force them out of entrenched cover positions.	Medic Operative
		Vanguard	Biotic / Combat	M1: A powerful combatant, able to combine the offensive powers of the Adept and the Soldier. They have access to various weapons and armor, as well as biotics. Gameplay focus is on taking down enemies with quick and brutal force. M2 / M3: Feared for their high-risk high-reward combat style, closing quickly on enemies and destroying them at close range with weapons and biotic abilities.	Nemesis Shock Trooper
		Sentinel	Tech / Biotic	M1: Able to combine tech and biotics to manipulate the environment, disable and track enemies, or defend the party. Gameplay focus is on protecting the party using kinetic barriers and healing it with advanced medical training. M2: While they lack the focus of adepts and engineers, they are versatile and can handle any situation. Sentinels are equipped with the most advanced ablation armor system to keep themselves safe. M3: In addition to complete weapons training, Sentinels are equipped with an advanced shield that makes taking cover much less necessary and rushing their enemies much more productive.	Bastion Medic
		Infiltrator	Tech / Combat	M1: A tech-savvy warrior, able to win battles by quickly disabling and killing enemies. These soldiers focus on unlocking alternate routes, gaining access to good equipment, and obtaining an advantageous position over enemies in combat. M2: Tech and combat specialists with the unique ability to cloak themselves from visual and technological detection. Deadly at any range, Infiltrators are equipped with a wide variety of weapons, equipment and powers that can take down any enemy. M3: Tech and combat specialists with the unique ability to cloak themselves from visual and technological detection. Their inventory is stacked with a wide variety of weapons, equipment, and powers. Infiltrators are deadly at any range, but particularly so with a sniper rifle.	Commando Operative
		Explorer	Tech / Combat / Biotic	MA: A jack-of-all-trades, with abilities ranging from combat and tech to biotics.

Alien blood colors: The red, yellow, blue, green, and purple alien blood seen in-game exists in-real life:

• Red - Most vertebrates. The color is due to the presence of iron.
• Yellow - Beetles, sea squirts and cucumbers. Their blood contains high concentrations of vanabin, which contain vanadium that gives the blood its color. Vanabin does not transport oxygen and its purpose is still a mystery.
• Green - Most annelids (worms/leeches) and select lizard species. The color is due to the presence of a chemical called chlorocruorin. For certain lizards the color is due to high concentrations of bile that would be lethal in most other lifeforms.
• Blue - Crustaceans, octopus/squid, and mollusk. The color is due to the presence of copper.
• Purple - Brachiopods and select marine worms. The color is caused by the protein hemerythrin used to transport oxygen.

Asari Reproduction:

Asari reproduce is similar to Bdelloidea, a class of female only rotifers found in freshwater habitats all over the world. They are often referred to as "ancient asexuals" because they rely exclusively on parthenogenetic reproduction - development of an embryo from an unfertilized egg cell.

Extra Krogan organs:

Many animals have "extra" organs, like squid's three hearts or the three jaws and 32 brains (physiologically; not anatomically) of a leech.

Levo vs Dextro:

Molecules based on carbon atoms can have up to four atoms attached to a central carbon. If you imagine this as a tetrahedron (d4, if you're a tabletop gamer) then you'll notice that you can actually arrange those four atoms in two different ways that cannot be reconciled by rotating the molecule. If they're arranged one way, it's (arbitrarily) named a levo- or left-handed molecule. If it's arranged the other way, it's a dextro- (right handed) molecule. Enzymes are built to attach to specific molecular geometries, and if they don't match the molecule, they don't work. So imagine if you will an enzyme that is designed to break a protein down into its constituent amino acids, so they can be re-used to build bodily proteins. This protease is shaped to grab onto L-amino acids and ignore everything else. When confronted by a D-amino acid, it quite simply won't grab on, which means the protein doesn't get digested, and is quite useless to the organism.

Out of the major food molecules, protein and carbohydrates exhibit chirality, fats do in triglyceride (but not free fatty acid) form. Minor food molecules such as volatile flavor compounds and vitamins vary based on the particular molecules. Interestingly, ethanol is non-chiral, so Tali's need for Turian brandy is a curious case, and is either a case of the writers not being biochemists, or the possibility that Quarians and Turians do not have ethanol dehydrogenase, an enzyme to break down ethanol, and instead rely on some other form of alcohol for intoxication.