Nucleus, it contains genetic material.
Plants stomata allow it to transpire and is also a mechanism used to 'suction' or 'pull' the water through the xylem
It is possible for large molecules to enter a cell by a process called endocytosis, where a small piece of the cell membrane wraps around the particle and is brought into the cell. If the particle is solid, endocytosis is also called phagocytosis.
A marine biologist is examining the effects of oil pollution on a population of birds known as seagulls (Larus canus). She is particularly concerned that oil pollution may reduce the number of eggs raised in a seagull nest. During one breeding season, she counted the number of eggs present in a sampling of six seagull nests near each of the 14 refineries throughout the state. She discovered that seagulls laid and raised an average of four eggs per season. To confirm her hypothesis, the researcher must now examine seagull nests that have not been exposed to oil pollution. The researcher believes she is correct, and so expects to find D) 4-6 eggs per nest.
There are so many examples for that in different areas, like TPBA experiment carried out in our lab recently.Here's one link: http://www.alfa-chemistry.com/tpba-cas-172285-72-2-item-294462.htm