Regeneration in planarians depends on the presence of stem cells called neoblasts. These cells are distributed throughout the body and, when part of the worm has been amputated, they are activated to reform the tissues that have been removed.
Answer:
The correct answer is "It prevents spontaneous muscle's contraction".
Explanation:
Muscle contraction is produce by the interaction of actin and myosin filaments. Basically, myosin binds to the active sites of actin, which produces a protein complex (known as actomyosin) that allows that the filaments slide past each other and generate a contraction. When troponin and tropomyosin block the active sites of actin prevents spontaneous muscle's contraction, because a nervous impulse is needed to remove the inhibitors and that myosin starts the contraction.
Answer:
response to stimuli / tropism
Explanation:
The plants and animals always respond to stimuli. It is an innate character of all living things. When a bright light falls on the eye, it closes immediately. This is responding to the stimuli. When someone touches the leaves of touch-me-not plants it closes its leaves due to the external stimuli.
The plants respond to the light. Because it does photosynthesis in the presence of light. Therefore, the leaves and branches of the plants always bend towards the light. This process is called phototropism.
Similarly, the roots of the plants move towards gravity under the ground. This is called geotropism.
Besides phototropism and geotropism, other types of stimuli are there - hydrotropism(response to the water), chemotropism(response to certain chemicals).
That's why the plants growing on the windowsill move towards outside where light comes.
secreted by the gonadotropic cells of the anterior pituitary gland, and regulates the development, growth, pubertal maturation, and reproductive processes of the body
