Answer:
Mold fossil.
Explanation:
The clamshell shaped cavity is a mold fossil owing to the fact that the clamshell died, its body deteriorated but while it is deteriorating it is being covered by sediment. As a result when the clamshell completely disappears it will leave an impression on the sediment, in other words, it is a mold of the prehistoric clamshell.
Answer:
T-tubules (transverse tubules)
Explanation:
T-tubules, also known as transverse tubules, are narrow tubes that are continuous with the sarcolemma (i.e., the cell membrane of striated muscle cells). In skeletal/cardiac muscle cells, T-tubules form invaginations of the sarcolemma that contain many ion channels involved in excitation-contraction (e-c) coupling of muscle cells. Thus, transverse tubules function to conduct the action potential from the cell membrane (sarcolemma) to the interior of the muscle cell.
An element is also a pure substance. The reason for this is because an element contains only one type of particle.
Option A is correct
Carbon cycle :
- CO2 is given out when organism breathe
- Plants gather this CO2 to produce oxygen
- Oxygen that is produced by the plants is used for other organism's breathing which will given out another CO2 and repeat the cycle
Water Cycle :
- Water from the sea and lake is evaporated and Turned into Clouds
- When atmosphere cool it down, these clouds will condense and turn into rain
- Eventually this rain will flow back to the lake or sea and it will repeat the cycle
hope this helps