Make(s) the walls of plant cells strong and rigid.
a. pectins
b. gums
c. oligosaccharides
d. cellulose

The correct answer is D. Cellulose is what makes the walls of plant cells strong and rigid. Cellulose is a polysaccharide that is very important for their structural role in animals and plants. It gives rigidity to the cells of a plant.

The scientific method is a series of steps followed by scientific investigators to answer specific questions about the natural world. it involves making observations, formulating a hypothesis, and conducting scientific experiments.the steps of the scientific method are •observation-the first step of the scientific method involves making an observation about something that interests you•question-once you've made your observation, you must formulate a question about what you have observed. •hypothesis-once you've made your observation, you must formulate a question about what you have observed. •experiment-once you've developed a hypothesis, you must design and conduct an experiment that will test it.•results-the results are where you report what happened in the experiment. •conclusion-the final step of the scientific method is developing a conclusion.i hope that this you : )