The identifying features of a dicot angiosperm are:

1. Tap root system:
A dicot angiosperm typically has a tap root system, which means it has a main root (taproot) that grows vertically downward and gives rise to lateral roots. The taproot is usually thick and helps anchor the plant in the soil, providing stability. It also enables the plant to access deeper water and nutrients, making it more drought-resistant compared to fibrous root systems found in monocots.

2. Leaves with reticulate venation:
Another distinguishing feature of dicot angiosperms is the presence of leaves with reticulate venation. Reticulate venation refers to a network of veins that branch and interconnect, forming a complex pattern on the leaf surface. This network of veins provides support and transportation of water, minerals, and sugars throughout the leaf. Examples of dicot leaves with reticulate venation include maple, oak, and rose leaves.

3. Seeds with two cotyledons and enclosed in fruit:
Dicot angiosperms have seeds with two cotyledons, which are embryonic leaves that serve as a food source for the developing plant. These cotyledons can be seen when the seed germinates and the embryo emerges. In contrast, monocots have seeds with a single cotyledon. Additionally, dicot seeds are enclosed in fruits, which are mature ovaries that protect and aid in the dispersal of seeds. Fruits can take various forms, such as berries, nuts, and capsules.

Conclusion:
The correct answer is option 'D' (All of the above) because dicot angiosperms possess all the mentioned features, including a tap root system, leaves with reticulate venation, and seeds with two cotyledons enclosed in fruits. These features help differentiate dicots from monocots and are important for their survival, growth, and reproduction.

A