Input: Article: Additionally, the Italian Eritrea administration opened a number of new factories, which produced buttons, cooking oil, pasta, construction materials, packing meat, tobacco, hide and other household commodities. In 1939, there were around 2,198 factories and most of the employees were Eritrean citizens. The establishment of industries also made an increase in the number of both Italians and Eritreans residing in the cities. The number of Italians residing in the territory increased from 4,600 to 75,000 in five years; and with the involvement of Eritreans in the industries, trade and fruit plantation was expanded across the nation, while some of the plantations were owned by Eritreans.

Now answer this question: How many factories were in Eritrea by 1939?

Output: around 2,198

Input: Article: Time appears to have a direction—the past lies behind, fixed and immutable, while the future lies ahead and is not necessarily fixed. Yet for the most part the laws of physics do not specify an arrow of time, and allow any process to proceed both forward and in reverse. This is generally a consequence of time being modeled by a parameter in the system being analyzed, where there is no "proper time": the direction of the arrow of time is sometimes arbitrary. Examples of this include the Second law of thermodynamics, which states that entropy must increase over time (see Entropy); the cosmological arrow of time, which points away from the Big Bang, CPT symmetry, and the radiative arrow of time, caused by light only traveling forwards in time (see light cone). In particle physics, the violation of CP symmetry implies that there should be a small counterbalancing time asymmetry to preserve CPT symmetry as stated above. The standard description of measurement in quantum mechanics is also time asymmetric (see Measurement in quantum mechanics).

Now answer this question: Which law states that entropy must increase over time?

Output: the Second law of thermodynamics,

Input: Article: The current–voltage characteristic of an LED is similar to other diodes, in that the current is dependent exponentially on the voltage (see Shockley diode equation). This means that a small change in voltage can cause a large change in current. If the applied voltage exceeds the LED's forward voltage drop by a small amount, the current rating may be exceeded by a large amount, potentially damaging or destroying the LED. The typical solution is to use constant-current power supplies to keep the current below the LED's maximum current rating. Since most common power sources (batteries, mains) are constant-voltage sources, most LED fixtures must include a power converter, at least a current-limiting resistor. However, the high resistance of three-volt coin cells combined with the high differential resistance of nitride-based LEDs makes it possible to power such an LED from such a coin cell without an external resistor.

Now answer this question: What feature do most LED fixtures need to have?

Output:
a power converter