Answer:
The statement is true
Explanation:
Hematopoietic stem cells give rise to myeloid progenitor and lymphoid progenitor and these two progenitors give rise to many immune cells. Dendritic cells are produced by both the progenitors and macrophages are produced by myeloid progenitor.
Both macrophages and dendritic cells are phagocytes. In phagocytosis, the foreing particles are injected by these phagocytes and they are destryoyed by the action of digestive enzymes present in these phagocytic cells.
Macrophages are present in tissue and if they are present in blood they are called monocytes. Therefore the statement is true.
the correct answer is carbohydrates because this fat can produce both short and fast energy.
Given question is incomplete. Complete question has been attached.
Answer:
C. Excessive potassium has diffused out causing hyperpolarization.
Explanation:
The nerve action potential can be divided into following stages:
- Stimulus is detected by the cell in resting stage.
- Sodium channels in the membrane open from where influx of sodium ions occur which is called depolarization
- After a while, sodium channels close and potassium channels open from where efflux of potassium ions occur which is called repolarization.
- The membrane potential further lowers due to continous efflux of potassium ions which is called hyperpolarization.
- After a while potassium channels close and membrane returns to its resting stage.
In the given figure, stage 4 depicts hyperpolarization because the membrane potential has dropped to the lowest point below -70mV. Hence, option C is correct.
Answer:
Spongy bone is well adapted to accept stress in many directions, which makes it good for shock absorption
Explanation:
Spongy bone tissue is less compact and always present towards the interior of the bone and is covered by compact bone. Spongy bone tissue has lamellae that are arranged in an irregular pattern. The thin irregular columns of lamellae are called trabeculae.
The trabeculae of spongy bone tissues are precisely arranged along the line of stress. This feature of spongy bones allows them to resist the stress applied from many directions and to transfer the force making them a good shock absorber. The final arrangement of trabeculae is achieved only after the person learns the locomotory movements completely.
Answer:
Memory cells are specalised types Nerve Cells .
