Astudent hypothesizes that a goldfish will be more active in a bowl that has red gravel than in a bowl of grey gravel. to get this hypothesis, the student places one goldfish in a bowl with red gravel and another goldfish in a bowl with grey gravel. the color of the gravel is the variable in the experiment.

The correct answer will be- independent variable.

Explanation:

A scientific experimental design must include three types of variables which are independent variable (which can be manipulated), dependent variable ( which has to be tested and depending on the independent variable) and constant variable (which is kept constant).

In the given question, since the student wants to study the difference in the activeness of the goldfish in red and grey gravels, therefore, he performed the experiment with different gravels.

In this experiment, the independent variable is the color of the gravel as it can be changed as well as the dependent variable depends on this variable.

Thus, the independent variable is the correct answer.

if the hares very faster than they are now, and thus the lynx's hunting success rate drops because it will be harder to catch them, the rate that will change will be the pray-rate. the pray-rate will change because more hares will be able to survive, thus more individuals for reproduction, so the end result will be increasing population of hares.

the predator-rate will remain pretty much the same because there will be more than enough pray, but the hunting success rate is stagnant.