A model organism is a species that has been widely studied to understand a particular biological phenomena, normally used because they are easy to breed and maintain in a laboratory setting and has certain experimental advantage.
The criteria that Thomas hunt Morgan was looking for include; the model organism should be small in size, easy to keep in the laboratory and also able to produce large number of off springs in a short time.
<span>well i take this test before and the correct answer is :A They produce food by photosynthesis</span>
It is converted into chemical energy.
the answer is moon. the name tells you what you can't see. since in a solar eclipse you can't see the sun that means that the moon is in between us on earth and the sun. which is why we can't see it