This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: A physical USB device may consist of several logical sub-devices that are referred to as device functions. A single device may provide several functions, for example, a webcam (video device function) with a built-in microphone (audio device function). This kind of device is called a composite device. An alternative to this is compound device, in which the host assigns each logical device a distinctive address and all logical devices connect to a built-in hub that connects to the physical USB cable. Question: What are logical sub-devices referred to as?
device functions

Passage: Philadelphia's an annualized unemployment rate was 7.8% in 2014, down from 10.0%the previous year. This is higher than the national average of 6.2%. Similarly, the rate of new jobs added to the city's economy lagged behind the national job growth. In 2014, about 8,800 jobs were added to the city's economy. Sectors with the largest number of jobs added were in education and health services, leisure and hospitality, and professional and business services. Declines were seen in the city's manufacturing and government sectors. Question: Unemployment rate in 2014?
7.8%

Passage: Imported Chinese labourers arrived in 1810, reaching a peak of 618 in 1818, after which numbers were reduced. Only a few older men remained after the British Crown took over the government of the island from the East India Company in 1834. The majority were sent back to China, although records in the Cape suggest that they never got any farther than Cape Town. There were also a very few Indian lascars who worked under the harbour master. Question: When did Imported Chinese labor arrive?

1810