Mr. Mann's class conducted an experiment about plant response to the presence of water. They first planted pea seeds in the sand. To start with, they watered the seeds. Once the seeds began to grow, they reduced the water they gave the plants. Instead, they placed a porous container of water close to the growing plant to see if the plant's roots would grow towards the cup of water. In science language, this plant response is called hydrotropism. An illustration of the experimental design can be seen here. What is the manipulated variable in this experiment? A) plant root growth B) the sand used to grow the seeds C) limited watering, replaced by the cup of water D) the water used to germinate the seeds and get them growing

1. true.2. true.3. true.4. false.5. true.the concept of darwin's theory of evolution involves the idea that there are limited resources in a given living environment and that the organisms which live within have variations in their genetic make up due to random mating. the ones with beneficial genetic variations can express certain traits which give them an upper hand in surviving and reproducing in the said environment compared to ones who may have a more disadvantageous variation in traits. over time, the organisms with an upper hand will survive and reproduce more frequently and pass on their beneficial genes while the others die. the result is evolution, where we observe (usually, but not always) eventually, phenotypic distinct changes.