Answer:
The correct answer will be option-C
Explanation:
The rhythm of the heartbeat is controlled by the pacemaker of the heart called the sino-atrial node.
The SA node generates action potentials which trigger the contraction and relaxation of the atrium and ventricles. The membrane potential generation initiates by the depolarization of the cell membrane when the L type of Ca⁺² ions opens up and calcium ions enter the cell.
This depolarizes the cell until the potential threshold is reached which lies between the -40 and -30 mV.
Thus, Option-C is the correct answer.
Answer: a
Explanation:
Because the top predictors only eat meat, and not the plants, so if you take out the primary consumers, then the top predictors will begin to die out.
Answer:
On May 18, 1980, an earthquake struck below the north face of Mount St. Helens in Washington state, triggering the largest landslide in recorded history and a major volcanic eruption that scattered ash across a dozen states
Explanation:
In a desert, the climate is “hot” and “dry”.
Answer:
D) Cartilaginous synchondrosis
Explanation:
Cartilaginous synchondrosis is a joint in which the bones are joined to the hyaline cartilage or the hyaline cartilage joins the bones.
The synchondrosis is of two types- the temporary and permanent synchondrosis in which the temporary synchondrosis represents the growth plate or epiphyseal plate of the hyaline cartilage which connects the shaft of the bones to the end of the bone.
The thickness of the epiphyseal plate in the children does not change as the bone lengthens.
Thus, D) Cartilaginous synchondrosis is the correct answer.
