The average gestation period of a mammal is the time from fertilisation to birth.
The table below contains data about the average mass of adult females and the average gestation period for five different mammalian species:
| Species | Average maternal mass (kg) | Average gestation period (days) |
|---|---|---|
| Species P | 0.2 | 30 |
| Species Q | 1.5 | 40 |
| Species R | 1.5 | 270 |
| Species S | 12.0 | 60 |
| Species T | 18.0 | 65 |
Describe the relationship between average maternal mass and average gestation period.
In one of these species, the embryo undergoes delayed implantation, staying dormant for several months before it implants and begins development in the uterus. Using the information in the table, explain which species this is.
The placenta connects the developing embryo to the maternal blood supply. Describe the role of the placenta in the development of the embryo.
