<span>Embryos of many different kinds of animals: mammals, birds, reptiles, fish, etc. look very similar and it is often difficult to tell them apart. </span><span>
This shows that the animals are similar and that they develop similarly, implying that they are related, have common ancestors and that they started out the same, gradually evolving different traits, but that the basic plan for a creature's beginning remains the same.</span>
Answer:
Ecological footprint estimates the requirements of renewable resources that a population consumes to live a particular lifestyle. Some ecologists are concerned because the result of the ecological footprint shows that the demand of the population is increasing in comparison to the supply of nature.
For example in India, the ecological footprint shows negative impact of population demand over supply of nature.