The answer to this question would be: <span>b.electromagnetic or weak nuclear
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The electromagnetic force can be repulsive or attractive because it was influenced by the magnetic charge. The same charge (positive with positive) will be repulsive but different charge will be attractive(negative and negative). The gravitational force will always be attractive, not repulsive.
Weak nuclear can do both like electromagnetic force.
The answer is : randomization was not used in sample selection. The major difference between experimental and quasi-experimental designs is lack of randomization in sampling selection.
Underwater living faces many of the same life support challenges as living in space. ... But in the future, underwater habitats might provide their own oxygen with artificial gill technology to extract dissolved air from the sea water
Since humans do not have gills, we cannot extract oxygen from water. Some marine mammals, like whales and dolphins, do live in water, but they don't breathe it. They have developed a mechanism to hold their breath for long periods of time underwater.
To put these depths into perspective, three American football fields laid end to end would measure 900 feet (274.32 m) long — less than the distance these divers reached underwater. Most recreational scuba divers only dive as deep as 130 feet (40 meters), according to the Professional Association of Diving Instructors.
Answer:
The correct answer is option D. Light and some other factors are necessary for chlorophyll production
Explanation:
By this experiment, it is clear that light is the major factor that helps in the production of chlorophyll in seedlings or plants. In this study, placing the seeds in the light turns 75 seedlings green which is possible by the production of the green pigment, chlorophyll only. So, it is proved that light is a key factor in the production of chlorophyll.
Besides light, there must be some other factors (mineral nutrition and chemical metabolites) that also play role in the production of chlorophyll or increase or decrease of the chlorophyll production as few seedlings did not turn green in the study.
The other plant cell is e
