I'm pretty sure it's recessive?
The controlled experiments are performed by the scientists, when they want to study the changes in the sample on changing a single variable. So, the correct answer is option (b).
In case, all variables are kept same, no changes would be observed in the experiment sample. A controlled experiment can be performed on living thing as well as non living. But, controlled experiment cannot be performed on the things which are influenced by a lot of variables, as they cannot create realistic results. So, the option (a), (c), and (d) are incorrect.
Using a slow- and fast-growing variant of bamboo, Wei and colleagues looked at cell division, growth, and gene expression (through transcriptomics, which measures all the genes being expressed by an individual) to discover which genes may be responsible for fast growth in bamboo. They found that the slow-growing variant had reduced expression of genes relating to cell wall construction, the plant hormone auxin (important for cell growth and cell division), and had irregular cell growth and cell walls. Wei and colleagues suggest that a reduced ability to produce and perceive auxin, combined with a weakened cell wall, are responsible for the slow growth seen in the bamboo variant.
Primary succession can occur in essentially lifeless areas or regions in which the soil is incapable of sustaining life as a result of such factors as lava, sand dunes, or rocks left from a retreating glacier.