Hello!
An initial observation is the first thing a scientist notices about a topic before conducting the experiment. We can see that it is the first thing in the paragraph in this case, that dandelions grow as unwanted weeds in many lawns.
The hypothesis is the guess about the result of an experiment made before the experiment is conducted. In this case, it is that a weed killer (Killimal) would kill all the dandelions while leaving the grass healthy. This is not specifically a guess made by the scientist, but more like a prediction he wanted to verify.
An independent variable is the variable being changed in the experiment by the scientist. Here, it is whether Killimal was sprayed or not.
The dependent variable is the variable being measured, and the one being affected by the independent variable. His observation would be whether the grass and dandelions would be killed. This is because the weed killer would be directly affecting whether or not these would be killed.
The control variables are ones which are kept the same in the experiment as to not interfere with the final results. In this case, it would be the density of dandelions, the amount of sunlight, and the amount the plants were watered. These were kept exactly the same, as they could've affected the dependent variable if changed.
The control group was the one that is not impacted by the independent variable. The control group makes sure that it actually is the independent variable affecting the dependent, and it isn't some outside unknown variable. This would be the plot without the Killimal.
The experimental group is the one being experimented on from the independent variable. This would be the plot with the Killimal. 
Hope this helps!
 
        
             
        
        
        
Answer: Hypothalamus 
The brain coordinates the physical changes that occur during puberty and the hypothalamus plays an especially important role in this process.
Explanation:
Since the hypothalamus controls the secretion of hormones from the pituitary gland, and the pituitary gland, also known as master gland, controls the activities of all other glands like the following:
- gonads (ovaries and testes), responsible for producing many of the sex hormones and hence, development of sexual characterictics
- thyroid, responsible for producing thyroxine, responsible for body metabolism and development.
Thus, hypothalamus plays important role in puberty
 
        
             
        
        
        
Answer:
A stream of nasty-tasting blood squirts from the toads eyes, straight into the coyote's mouth. The coyote steps back, shaking its head from side to side in disgust. It retreats, wiping its muzzle, while the uninjured toad skitters away to safety. 
 
        
             
        
        
        
Answer:
Due to absorption of more water.
Explanation:
A Cotton shirt takes more time to dry as compared to a synthetic shirt due to absorption of more water by the cotton fiber as compare to other fiber. Cotton absorbs much more water than other synthetic fibers, and attached to the molecules of cotton for longer period of time which means cotton fibers take more time to dry as compared to synthetic fiber which absorb little amount of water and loosely attached to the molecules of fiber.