<span>Controlled experiment is an experiment done under controlled conditions in which only one variable at a time is changed in order to isolate the results. An alternative to a controlled experiment would be a correlation study. A correlation study is a research method in which two variables are compared (what are the similarities and the difference between them). So, correlation study is a type of controlled experiment in which ove variable is changed and the dependence with another variable is analyzed.</span><span />
For the first question, I would say a line graph. And the one about the human heart, I need some more information.
<span>Some mutations don't have any noticeable effect on the phenotype of an organism. This can happen in many situations: perhaps the mutation occurs in a stretch of DNA with no function, or perhaps the mutation occurs in a protein-coding region, but ends up not affecting the amino acid sequence of the protein.</span>
Endocytosis is when a a cell engulfs material into the cell and exocytosis a form of waste where the cell gets rid of materials.
