All plants are autotrophic.
Autotrophic means he doesn't need another living thing to live(for eating) but that he makes his own food (photosynthesis). (auto means itself).
Heterotrophic means he needs others to keep on living. Like animals. All animals need to eat and can't make their own food with only sunlight, CO2 and water. They need food, which may be plants or other animals. That depends on the animal.
The D period refers to the stage between the end of DNA replication and the splitting of the bacterial cell into two daughter cells. In cells with a nucleus, as in eukaryotes, the cell cycle is also divided into three periods: interphase, the mitotic (M) phase, and cytokinesis.
It would be D because would be small and you wouldn't feel it. For answer A, the scientist could feel it. For answer B, you can kind of feel it or feel it. For C, It can definitely feel it. So the answer would be d.