How old are bees from the beginning?

How old are bees from the beginning? There are fossils that are very similar to bee nests, which were found in a 200 million years fossilized tree. The reading states three reasons that contradicts the 200 million years existence of bees: No fossil of actual bees, absence of flowering plants, and structure lack some details. On the contrary, the lecturer cites three proofs to reject the points in the reading. First, the writer explains the oldest bee preserve belonged to 100 million years ago, however, the discovered fossils are two times older. Conversely, the lecturer believes maybe bees' bodies were unable to preserve for that long. In addition, the substance that bees’ bodies can remain as a fossil is a specific substance that is very rare, as a result, bees had a little chance to be preserved. Second, the passage points out bees only feed on flowering plants, despite these plants emerged just 75 million years later. By contrast, the professor declares bees bossibly nourished from other plants, for instance pine trees that had not flower on them. Moreover, there was a room for them to change their source of food during history. Finally, the writer notes, although modern bees guard their nest with a cap to confront water, discovered fossils lack this part and bring about the theory that believes the nest fossils were created by other insects. In contrast, the lecturer claims current bees use a chemical in the cap of the nest, similarly this substance exists in the discovered fossil. To sum, the writer believes bees' arrival in the earth is shorter than 200 million years and proposes an array of reasons to support the idea of the reading; Conversely, the lecturer contradicts the writer theories using various reasons and illustrations.