Answer:
Hey there.
<em><u>There are three types of scientific investigations: descriptive, comparative, and experimental scenitific investigations.
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fist we have <em><u>Descriptive</u></em> scientific investigations.
Descriptive investigations use careful observations and measurements to develop findings.
Then we have <em><u>
comparative </u></em>Investigation.
comparative investigations Involve collecting data on different populations/organisms, under different conditions (Times of year, locations), to make a comparison. for Example, Using a hand lens to examine the color and texture of four different rocks.
Lastly we have <em><u>experimental</u></em> scientific investigations. 
Experimental investigations involve a process in which a "fair test" is designed and variables are actively manipulated, controlled,
I hope it helped!!!
<em>Wbob1314</em>
 
        
             
        
        
        
Answer:
The electron density of a polar bond accumulates towards one end of the bond, causing that end to carry a slight negative charge and the other end a slight positive charge. Likewise molecules in which there is an accumulation of electron density at one end of the molecule, giving that end a partial negative charge and the other a partial positive charge, are called polar molecules.
 
        
                    
             
        
        
        
I think the answer is C because minerals are broken down into the rock
        
             
        
        
        
Answer: Option (A) is the correct answer.
Explanation:
Beaches are the places which are part of shore of an ocean, sea, large river etc.
There are pebbles and sand at the shore of a beach. Waves of water in an ocean always change the ocean due to  erosion and addition of sand.
It is the force acted by the wave that pushes or pull the sand in different directions every time the wave comes.
So we can conclude that the statement beaches are always changes due to factors such as waves adding and eroding sand best describes beaches.
 
        
                    
             
        
        
        
Calcium levels in the body are maintained by hormones. If the blood calcium level rises above a set point, calcitonin is secreted by the thyroid gland and sets into motion responses to lower the blood calcium back to the set point. If the blood calcium level falls below a set point, the parathyroid gland secretes parathyroid hormone that sets into motion responses to raise the blood calcium. These homeostatic responses are examples of:
a. positive feedback
b. effectors
c. sensors
d. negative feedback
Answer:
d. negative feedback
Explanation:
Negative feedback responses are the ones that counteract the change. Any alterations in the internal body conditions such as blood calcium levels are sensed by receptors. The information is sent to the brain which in turn commands the effectors such as endocrine glands to secrete the required hormones to restore the normal conditions. Here, changes in the calcium levels are counteracted by the secretion of calcitonin and parathyroid hormones and the calcium is maintained within a narrow range. This represents negative feedback.