You've made the hypothesis that the less rainfall a cactus plant gets, the taller it will grow, since cactuses like dry conditions.
What should be the dependent variable in an experiment designed to test this hypothesis?
A. the height of the cactus plants
B. the hours of sunlight the cactus plants get
C. the amount of rain falling on the cactus plants
D. the type of soil the cactus plants are growing in

b

Explanation:

because since the cactus likes dry environments, you are supposed to measure the amount of sunlight the plant absorbs

hopes this helps :)

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.