Let's take a look at the tools given in the answer choices:

A thermometer is used to measure the temperature of something, or to determine how hot or cold something is. 

A scale is used to determine the weight of an object. 

A measuring cup is used to determine the amount of something. Measuring cups are often used in baking. For example, if a recipe called for two cups of sugar, you would use a measuring cup to measure out two cups of sugar.  

A ruler is used to measure the length of something. 

Based on the question, we are trying to determine the temperature, so we would use a thermometer. 

Let's take a look at the tools given in the answer choices:

A thermometer is used to measure the temperature of something, or to determine how hot or cold something is. 

A scale is used to determine the weight of an object. 

A measuring cup is used to determine the amount of something. Measuring cups are often used in baking. For example, if a recipe called for two cups of sugar, you would use a measuring cup to measure out two cups of sugar.  

A ruler is used to measure the length of something. 

Based on the question, we are trying to determine how long the desk is, so we would use a ruler. 

For plants to grow and survive, they need sunlight and water. Water is collected through the roots of the plant and absorbed from the soil. Sunlight is collected through the leaves of the plant to use in the process of photosynthesis to make food. Plants cannot live without sunlight and water.

If Justin wants to plan an investigation, an important part is to have the right supplies or materials. Justin will need two plants, one to place in the sunlight and one in the dark, water for the plant in the sunshine, a ruler to measure growth, and paper and pencil to record observations. The other lists are incomplete or have materials that are not needed for this investigation.

Most investigations or experiments start with a question. In this case, Brandon is wondering about keeping plants alive and helping them grow. A scientific question must be testable, meaning someone can collect data and observations, and it should be related to what the person was wondering. The correct answer choice is testable and related. Water and sunlight are essential to a plant's survival, so they would be good variables to test.

A hypothesis is stated before an investigation or experiment is performed, and the evidence collected will either support or will not support the prediction. A hypothesis should be reasonable and related to the topic. Virginia is testing what would happen to plants without water or sunlight; these are two critical pieces to a plant's survival. Using background knowledge or personal experiment, a prediction can be made that the plants will not survive. "I believe the rose plants will not survive without sunlight or water. They will wilt and die over time." is the most reasonable hypothesis.

In this investigation, Nick is only testing if plants grow better somewhere dark or sunny. The water the plants receive should be the same, and there should be some plants in the sun and some in the dark so they can be measured and observed. There have to be plants in both locations to compare growth.

The best title for Christopher's experiment would be "Do Plants Need Sunlight and Water to Grow?". It is short and includes all of the vital information. It doesn't leave anything out or have any parts that are irrelevant to the experiment.

Jennifer is testing whether plants can survive without sunlight and water, so those are the only two variables that will change. Everything else in the investigation should remain the same. The same pots, same dirt, same amount of water each day, same type of seeds, and the same amount of sunlight or darkness should be maintained throughout the investigation. "Get four identical pots and fill each with the same amount of dirt—plant three sunflower seeds in each container—place two in a window and the other two in a dark closet. Water one of the plants in the window daily, water one of the plants in the dark closet daily—record plant growth and observations." is the most controlled and complete investigational plan.

The only test variable in this investigation is whether the plant gets water or not. Andrew is testing if water is needed for plants to survive. All of the test plants should be in the same location, and some should get water while others do not so they can be compared to one another. If all the plants get water, then Andrew will not know what would happen without water. If he has some plants in different locations, he won't know if it is the water or the area that stopped a plant from surviving.