The lipids are a diverse group of organic substances including triglycerides,phosphlipids and the sterols
Answer:
Observers ahead of the wave observe an apparent increase in wave frequency
Explanation:
This is the Doppler Effect. The frequency of a wave increases when the source approaches the observer and decreases as the source recedes.
B, C, and D are wrong. Observers behind the source notice a decrease in frequency.
Answer:D
Explanation:
you don’t have to think about moving your blood vessels which makes it a smooth muscle.