Models need to be changed when a. they are based on experimental data b. scientific understanding changes c. they represent a phenomenon d. they are designed to answer a question select the best answer from the choices provided a b c d

the answer is a because if the model is based on experimental data it wont be good unless it has been tested.

B

Explanation:

scientific understanding changes

humans, along with other animals and plants, have linear chromosomes that are arranged in pairs within the nucleus of the cell. the only human cells that do not contain pairs of chromosomes are reproductive cells, or gametes, which carry just one copy of each chromosome.

d) center of the mid-ocean ridge

give brainleysest

sinserly,

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