To solve this problem, we need to analyze the given statements:$\newline$Assertion (A): Late wood has fewer xylary elements with narrow vessels.$\newline$Reason (R): Cambium is less active in winters.$\newline$Let's break down each statement:$\newline \bullet$Assertion (A):$\newline$ - Late wood, also known as autumn wood, is formed towards the end of the growing season.$\newline$ - It is characterized by having fewer xylary elements and narrower vessels compared to early wood.$\newline$ - This is due to the reduced growth activity as the growing season ends.$\newline$ - Hence, Assertion (A) is correct.$\newline \bullet$Reason (R):$\newline$ - Cambium is a layer of actively dividing cells in plants that contributes to secondary growth.$\newline$ - During winter, the activity of the cambium decreases significantly due to lower temperatures and reduced metabolic activity.$\newline$ - This reduced activity results in the formation of late wood with narrower vessels.$\newline$ - Hence, Reason (R) is correct.$\newline$Now, let's determine if (R) is the correct explanation of (A):$\newline \bullet$The reason explains why late wood has fewer xylary elements with narrow vessels.$\newline \bullet$It highlights the reduced activity of the cambium during winter, leading to the characteristics of late wood.$\newline$Therefore, (R) is indeed the correct explanation of (A).$\newline$Thus, the most appropriate answer is Option 1: Both (A) and (R) are true and (R) is the correct explanation of (A).