What are the challenges to finding the beyond earth and beyond our solar system

but there is no

i guess you forgot putting it.

1. is geographic distribution

2 is increasing complexity

3 is transitional forms

there is not 1 highest source of protein, but there are many; meats, fish, poultry, seafood, cheese, eggs, yogurt and milk. the only non complete animal food that is beneficial is gelatin.

sorry if this did not , have a great day!