Phloem is the food conducting tissue that has a two-way flow.
Explanation:
Plants prepare food on their own and plants also have conductive cells that carry out transportation process. Plants are divided into two types based on their conductive system i.) vascular plants ii.) non vascular plants.
Vascular plants are those plants which have special conductive cells called phloem and xylem.
Xylem transports water from roots of the plants to other parts of plants and also provides mechanical support to plant. It is uni-directional.
Phloem is the food conducting tissue that transports food to plant and also have bi-directional movement.
The right answer is <span>Refractory period.
At the moment when the action potential is emitted, the fiber being depolarized, it is impossible to depolarize it again. It is, therefore, necessary to wait until the membrane potential returns to a value below the critical threshold in order to be able to excite it again. We are thus led to distinguish two periods that characterize its excitability.
An absolute refractory period: during which any stimulation, even supraliminal, is ineffective since the fiber is already depolarized.
A relative refractory period: during which a second action potential can be omitted provided that the depolarization produced by the excitation reaches the critical threshold, which implies that it is more important since the value of the resting potential has not been restored yet.</span>
Answer: D) By decreasing the activation energy of a reaction
A catalyst is a substance that speed up the rate of chemical reaction without affecting the product of the reaction. They only affect the rate of reaction not the yield of reaction.
Catalyst provide an alternative reaction pathway that has lower activation energy than that of uncatalysed reaction. It increases the frequency of collision and because of these greater collision which lowers the activation energy of the reaction.
Answer and Explanation:
Internal fertilization is characterized by sperm fertilizing the egg within the female. More protection against outside environments and predators, and therefore a higher chance of surviving until birth
. The young develop within the female, receiving nourishment from the mother’s blood through a placenta. Less chance of desiccation of gametes. Internal fertilization also enhances the fertilization of eggs by a specific male since the females are more selective of their mates thus increasing chances of gametes meeting
. Even though fewer offspring are produced through this method, their survival rate is higher.
