<span>Facilitated diffusion
Diffusion
occurs because of the movement of molecules from the region of higher
concentration to the region of lower concentration. This movement of
molecules occurs due to a thermal motion. Diffusion normally occurs
between two compartments having difference in concentration. In case of
fluid it moves from the region of higher concentration to the region of
concentration until a balance is reached. The process of diffusion is
very important for the humans as well. The oxygen that humans breathe in
gets diffused with the blood.<span> </span></span>
The question is; would a drug that binds irreversibly to these receptors be an effective contraceptive in mammals?, the answer is;Yes; because if the receptors are blocked the sperms will not be able to penetrate the zonal pellucida of the egg. Contraceptives prevents pregnancy by interfering with the normal process of ovulation, fertilization, and implantation.
Answer:
Stimuli must be sensed in order to respond.
Explanation:
Classical conditioning can be defined as a learning process which typically involves repeatedly pairing two stimuli: conditioned stimulus and unconditioned stimulus.
Simply stated, it is a learning procedure that helps us to understand when a neutral stimulus is paired with a conditioned response.
An example is the process of salivating in response to the aroma of a meal being prepared in the kitchen.
Also, operant conditioning can be defined as an associative learning process which involves reinforcing the strength of a behavior.
Stimulus in biology can be defined as an obvious change in either the chemical or physical structure of an organism' environment (either external or internal). Thus, all living organisms (both animals and plants) respond to changes in their environment and consequently, an appropriate response or reaction is made. Also, stimulus arising from within the organism is known as internal stimulus while those from its environment are known as the external stimulus.
In organisms, the specialized cells that detect stimulus are generally known as sensory receptors while a group of these receptors is referred to as sense organ.
Hence, the senses are necessary for behavior because stimuli must be sensed in order to respond.
