Which structures do plant cells have for making food that animal cells do not?

If a robot fixed another robot is it a engineer or doctor?

Hummingbirds drink nectar from flowers, while robins eat plant seeds. what does this reduce?

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled