Read this response and predict the preceding dialog. Egg size tends to be proportional to the size of the adult bird, from the half gram egg of the bee hummingbird to the 1.5 kg egg of the ostrich.

A dialog between 2 people:
Speaker A) Why do birds sit on their eggs
Speaker B) Tipping the big end upwards improves oxygen flow to the large head, with the physiologically demanding eyes and brain, that develops in the big end while the tail develops at the more pointed end.
Speaker A) why are the ends different sizes
Speaker B) In a 2017 publication in the journal "Science", mathematical modeling of 50,000 bird eggs data showed that bird egg shape is a product of flight adaptations and not the outcome of nesting conditions or a bird's life history.
Speaker A) what does the shape have to do with flying
Speaker B) A strong correlation was found between egg shape and flight ability on broad taxonomic scales, such that birds engaging in high powered flights usually maximize egg size by having elliptical shaped eggs while maintaining a streamlined body plan.
Speaker A) how big are the eggs
Speaker B) 