Answer:
The correct answer is - option C) sign language.
Explanation:
Washoe was a chimpanzee used in a research experiment. According to Beatrice and Allen Gardner, this chimpanzee is the first non-human to learn and communicative with the help of American sign language. Washoe learned about 350 signs of ASL, an American sign language. It was part of the research experiment on animals.
Thus, the correct answer is - optic C.
To confirm the above hypothesis, Maria should perform an experiment to prove that xylem is responsible for the transport of coloured water through the plant. This is called the ascent of sap.
A suitable plant having a tender, semitransparent stem should be selected. The root system of the plant should be cut off and the twig has to be placed half-immersed in a coloured solution of water for about one hour. Later, when the plant is observed, parallely running streaks of coloured water can be seen through the semitransparent stem and other parts of the plant indicating that the xylem is involved in the upward movement of water.
An independent variable is a variable which change is not affected by that of another variable. By process of elimination you can take out B and C. An independent variable can also change so that takes out A. That leaves D.