The well - designed experiment test one factor at a time. The answer to the question above is letter A. 1. The items that are being tested are the independent variables and that they cause the dependent variables to change.
Answer:
Euglena is a single celled organism. It belongs to Kingdom Protista. Euglena is a eukaryotic organism that exhibit characteristics of both plants and animals. Some species of Euglena are photoautotrophs like plants which means they have ability to trap sunlight to produce food by the process of photosynthesis. Whereas, some species are heterotrophs like animals which means they obtain food by feeding on other organisms.
If scientists remove all of the chloroplasts from a Euglena, it will not be able to perform photosynthesis because chloroplast is an organelle that contains light sensitive pigments named as chlorophyll. Chlorophyll traps light energy from sun. Sunlight energy, along with carbon dioxide and water produces food in the form of glucose in plants and other photoautotrophs.
When a small populations' gene frequencies are changed drastically by chance alone it is called a genetic drift