→ Darwin believed that the need to adapt, in similar words, the changes occruing in the environment caused evolution.
The main cause of evolution, according to Darwin, was natural selection. Natural selection is a process in which a group of organisms with certain characteristics survive and thrive, in comparison to other organisms with different characteristics. This idea basically means that having some characteristics makes you suited for an environment.
And how would that ↑ explain Evolution?
Well, evolution is the change in species that occurs during time. But for you to change, there must be a cause for that change, which is none other than the need to survive, reproduce, etc.
→ As mentioned before, not all characteristics are enough to surive, and hopefully the image pasted below will help you.
Hope it helped,
BioTeacher101
Phagocytosis is the answer to this one :)
The Griffith's experiment, the Avery-MacLeod-McCarty experiment, and the Hershey–Chase experiments were the set of experiments that established DNA as the key hereditary molecule. The Avery-MacLeod-McCarty experiment was an extension to the Griffith's experiment. The heat killed virulent S strain cells of the Griffith's experiment were lysed to form a supernatant containing a mix of RNA, DNA, proteins and lipids from the cell. The supernatent was equally divided into 3 parts after the removal of the lipids. The 3 parts were respectively treated with an RNAase to degrade the RNA, DNAase to degrade the DNA and proteinase to degrade the proteins. The treated supernatant was then added into the culture containing the non-virulent R cells. In case of the supernatant treated with the DNAse, no transformation of R cells into S cells occurred. The transformation of R cells to S cells occurred in the proteinase and the RNAse cases. This indicated that DNA was the hereditary molecule and not protein or RNA.

Answer:
mitochondrion / mitochondria coming from the apex.