C. A wall of stones and mortar
This would act as a model describing the cell membrane.
Explanation;
A cell membrane is made up of a phospholipid bilayer with embedded proteins.
A cell membrane hold the different components of the cell together and to protect it from the environment outside the cell. It acts as a boundary between the inside environment and the outside environment of a cell.
It regulates the materials that enters and exits the cell; through selective movement of substances in and out of the cell.
Weather is an example of rapid environmental changes.
Explanation:
Environment refers to our natural world surroundings. Rapid means fast or quick. Weather around us keeps changing as the earth rotates and revolves around the sun. It changes depending on the month of the year or may change from day to night. You can also note the room temperature at different times in a day, it keeps changing mostly minorly but it does change. There are sunny, foggy, rainy, cold etc days and hence we can say that weather is example of rapid environmental changes.
The branching point on a cladogram represents a common ancestor. A cladogram is a diagram used in cladistics to show relations among organisms. However it is not an evolutionary tree since it does not show how ancestors are related to descendants, nor does it show how much they have changed.
Endocrine system regulation slowly happens but produces long-lasting effects, whereas nervous system regulation quickly takes place with short-term effects.
Endocrine system can regulate many things in the body that control the metabolism. The effect shouldn't be instant, but it should be good for long term effect. Nervous system need a much faster reaction because it responsible for "fight or flight" reaction. A slow nervous system will cause the organism caught by predator easier.
