Answer:
"Forays".
Step-by-step explanation:
As seen in the given paragraph, the author talks about a new venture, a brief act of getting into a new field of study. And the word that closely resembles/has the nearest/closest meaning to the required word is "forays".
Now, the word "foray" means a sudden intrusion or entry into a new or completely foreign area. This means the at of getting into unknown field/ area, making it an entry into something never done before. Thus, the word "forays" is the closest thing to the required word for "a brief venture into a new field".