Answer:
No one can see in total darkness. Fortunately, there’s almost always some light available. Even if it’s only dim starlight, that’s enough for your eyes to detect. What’s truly amazing is how little light is required for you to see.
Human eyes have two main features that help us see better in low light: the pupil’s ability to change size, and the eye’s two types of light-sensing cells.
Opening up to let in more light
Your pupils are the black areas at the front of your eyes that let light enter. They look black because the light that reaches them is absorbed inside the eyeball. It’s then converted by your brain into your perceptions of the world.
You’ve probably noticed that pupils can change size in response to light. Outside on a bright sunny day, your pupils become very small. This lets less light into the eye since there’s plenty available
Answer:
As the variables are not given, let us help with general explanation on manipulated variable.
Explanation:
A manipulated variable is an independent variable. In a scientific experiment, an independent variable can be described as a variable which can change naturally or which is changed by the researcher to check its effect on the dependent variable. The dependent variable is the variable which is under study and being tested.
For example, to check the difference in photosynthesis rate by light, the amount of light will be the independent variable and the rate of photosynthesis will be the dependent variable.
Answer:
Nope
Explanation:
that's only used in plants to make them grow or stronger
Primary sources means that it is original article or book created by an individual or sometimes a group of people. What types of primary sources are available? It might be surprising to know that a novel is a primary source. Other types of primary sources are paintings created by the artist. If it were a photocopy of the painting, then it would be a secondary source. Some other primary sources are letters, films, short stories, plays, poems, photographs, court cases, journal articles, newspaper events, and speeches. For instance, a speech by President Bush would be a primary source.
Secondary sources are sources that are written about primary sources. Secondary sources analyze, interpret, and discuss information about the primary source. If a magazine writer wrote about the speech President Bush gave on September 11th, it would be a secondary source. The information is not original, but it is an analysis of the speech.