Hello, teachers.

Would you read the following?

Literacy has long been considered the main evidence of a child's educational progress. As a result, more attention has been paid to the nature of the task facing children as they learn to read than to any other area of curriculum. Hundreds of reading programs and philosophies have been devised in the past 200 years, and many have achieved a degree of success. Usually, however, it is uncertain whether success is due to the qualities of an approach or to the enthusiasm with which it is promoted by its followers.

What does "the nature" mean in this context?
I checked the meanings of it in English-Japanese dictionaries, but I can't decide which meaning is the best suitable here.

Thank you very much in advance for your help on this.