Answer:
c. the plant root growing down into the soil
Explanation:
The plant root going down deep into the soil is an example of positive gravitropism. Gravity pulls everything towards the center of earth i.e. downwards and roots follow the direction of gravity automatically by growing downward towards soil that is why it is known as positive gravitropism. In short we can say that root favors the direction of gravity.
Shoot on the other hand show negative geotropism/gravitropism i.e. it grows towards the opposite direction of gravity. Shoot grow towards upside direction i.e. away from the surface towards sky.
Answer:
Osteon
Explanation:
Bone tissue may be of two types; compact bone tissue that form the outer hard covering of bones and spongy bone tissue that form inner soft portion of bone. Osteon are found in compact bone.
Osteons are cylindrical structures composed from clustre of Osteocytes and layers of extracellular matrix around a central canal connected by canaliculi for the transportation of blood. The haversian canal is surrounded by lamella that comprises the osteon. Osteons run parallel to long axis of bones and present in bones of many mammals, reptiles and birds. In some bones the stress or pressure in applied from few directions and osteons are aligned in that direction so they provide protection from bone bending or fracturing from compressive forces.
Answer:
b) In allosteric regulation, a small molecule binds to a large protein and causes it to change its shape and activity.
Explanation:
Allosteric regulation refers to the activity control of an enzyme by binding small molecules to regulatory sites on It. This binding causes an alteration of the protein conformation and consequently the shape of the active site and its catalytic activity are altered. Regulatory enzymes can act by either stimulating or inhibiting the activity of a protein.
Phytoplankton and Photosynthesis
Importance in Global Ecosystem
