Original Answer Provided: "Menes is the King who united Upper and Lower Egypt"
REVISED ANSWER:
Whilst it can be 'suggested' that Menes was responsible for the uniting of Upper and Lower Egypt, the serious lack of archaeological evidence to support Menes even existing as a living entity in his own right, and under that specific name, means it is not entirely accurate to state him as even a Pharaoh let alone a king responsible for the unification of Egypt.
The argument and debate around Menes and his existence is to whom he relates. Most Egyptologists and historians alike would have it that Menes is one and the same with Narmer (originally thought to be King of Upper Egypt and who leads the strongest claim to being responsible for the unification). Research into Narmer provides strong links between him and Menes, and some of the greatest Egyptologists of the last few centuries, such as Flinders Petrie were convinced they were one and the same.
(However some suggest, due to archaeological finds (and stories relating to both characters that are closely matched); that Hor-Aha (son of Narmer) is actually Menes.)
When you look into this deeper, you discover that is likely that Menes, King Scorpion, and Narmer could potentially all be the same person.
It is further suggested that Menes is the collective name for Ka, Scorpion and Narmer.
Failing that, it is quite possible that Menes is a simply a mythical or semi-mythical character.
Whilst the Egypt Historian Manetho has mentioned Menes, and credited him as the first ruler of Egypt, receiving the honour directly from the God Horus, his name does not appear on the Palermo Stone, and it is only much later in Egyptian periods that the name really begins to be associated with the early ruling of the civilization.
So to the original question posted - Given the stronger archaeological discoveries relating to Narmer over 'Menes' I believe the answer should be Narmer (archaeological discoveries have shown depictions of Narmer wearing the pschent, a crown with two halves representing the 'two lands' of Egypt - in particular the Narmer Palette). Though there could be an argument that potentially his son Hor-Aha played a part (which is possible given that the unification would likely have occurred gradually over many years rather than in a singular event); though the debate will no doubt rage on for many years to come.
This is unification. One way to remember:
UNIfication = UNIte
(UNITE MEANS TO JOIN TO THINGS TOGETHER, LIKE LANDS AND PEOPLE)
Upper & Lower Egypt were combined by the warrior-king Menes.
Menes the 1st pharaoh of the 1st Dynasty, unified Egypt in about 3000B.C.
King Narmer
The two Egyptian kingdoms, Upper and Lower Egypt, arose because the land near the First Cataract and the Nile Delta, respectively, was suitable for agriculture. They united around 3000 B.C.
Pharaoh Narmer (who may also have been called Menes) united the Kingdoms of Egypt.
King Tut ruled as Pharaoh for Upper and Lower Egypt for a few years
Upper Egypt and Lower Egypt
The two kingdoms were unified and a new crown was made, the fusion of upper Egypt's crown and lower Egypt's crown.
He united the separate Upper and Lower Kingdoms.
The two Egyptian kingdoms, Upper and Lower Egypt, arose because the land near the First Cataract and the Nile Delta, respectively, was suitable for agriculture. They united around 3000 B.C.
the capital of upper egypt was known as Teba(luxor) and the capital of upper egypt was in nile delta then the two were united by Mena the pharoh of upper egypt
King Narmer united Upper Egypt and Lower Egypt during his rule in the 1st Dynasty.
Pharaoh Narmer (who may also have been called Menes) united the Kingdoms of Egypt.
The two kingdoms were the Upper Egypt and the Lower Egypt.
Menes (Narmer) king of Upper Egypt united the two kingdoms in around 3000BC. (Upper Egypt was united with Lower Egypt, that is the White Crown was united with the Red Crown.)
There was Upper and Lower Egypt in pre-dynasty but these were united when the first pharaoh, Narmer, came to power. Since then they had been united.
upper egypt,, lower egypt and nubia
King Tut ruled as Pharaoh for Upper and Lower Egypt for a few years
King Menes united upper and lower Egypt
Upper Egypt and Lower Egypt