Question

an experiment was carried out to answer the question \does the ph of water affect the growth of radish plants?\ two groups of ten radish plants were set up. one group was watered with water having a ph of 3.0, and the other group was watered with water having a ph of 7.0. both groups of plants received the same amount and intensity of light, the same amount of water, and they were grown in the same type of soil. the heights of the radish plants were measured every 2 days for a period of 2 weeks.

1. which activity might help to increase the validity of this experiment? (1) repeating the experiment several times (2) using two different types of radish seeds in each group (3) using the same ph for both groups of plants (4) placing one set of plants in sunlight and one in darkness
2. what was the dependent variable in this experiment? (1) heights of the plants (2) ph of the water (3) temperature of the water (4) type of soil
3. write a hypothesis for the experiment above.

use the following scenario to answer 8 and 9. for most animals, the sex of the offspring is determined by sex chromosomes. in some species of reptiles, such as the painted turtle, there are no sex chromosomes. it has been discovered that the sex of the offspring is determined by the temperature of the nest in which the egg develops. a team of scientists decides to test which temperatures result in the greatest number of female or male eggs.

1. identify the independent variable in the experiment above:
2. identify the dependent variable in the experiment above:

Explanation:

Question 5:

Repeating an experiment multiple times helps account for random errors and variability, increasing the validity of results. Using different types of seeds, same pH, or different light conditions would either introduce more variables or remove the key variable being tested.

Question 6:

The dependent variable is what is being measured or observed and is affected by the independent variable. Here, the height of the plants is being measured as it may be affected by the pH of the water.

Question 7:

A hypothesis is a test - able prediction. For this experiment, it could be about the relationship between water pH and radish plant growth.

Question 8:

The independent variable is the factor that is deliberately changed or manipulated in an experiment. In the turtle experiment, it's the temperature of the nest.

Question 9:

The dependent variable is the outcome that is measured in response to changes in the independent variable. Here, it's the number of female or male eggs.

Answer:

Question 5: (1) repeating the experiment several times

Question 6: (1) heights of the plants

Question 7: If the pH of water is lower (more acidic), then the radish plants will grow less in height compared to plants watered with neutral - pH water.

Question 8: Temperature of the nest

Question 9: Number of female or male eggs