Answer: D) Pulmonary and aortic valves.
Explanation
There are two main heartbeats from a healthy heart.
The first beat is called the S1 or the lub, and it occurs when the atrioventricular valves (comprising the mitral and tricuspid valves) close.
The second beat is called the S2 or the dub, and it occurs when the semilunar valves (comprising the aortic and pulmonary valves) close.
Listening for heart beats is an essential part of cardiac auscultation.
When boys go through puberty their voices change and they start to grow hair on different area of their body such as their chest, face and pubic area. Also they will start to get acne
Answer:
Sediment in rivers gets deposited as the river slows down. Larger, heavier particles like pebbles and sand are deposited first, whilst the lighter silt and clay only settle if the water is almost still.
Answer:
C
Explanation:
Biodiversity is the difference and variation in a given area
Answer:
mitochondria
Explanation:
Mitochondria is known as power house of a cell
