Answer:
True
Explanation:
When the resting potential of the membrane is changed, the membrane becomes either more negative inside or less negative. This small deviation from the resting potential is called graded potential. A graded potential occurs when a stimulus triggers opening or closing of the mechanically gated or ligand-gated channels present in the plasma membrane.
For example, the presynaptic neuron releases neurotransmitters in response to a nerve impulse. The neurotransmitter binds to receptors present in the plasma membrane of the postsynaptic neuron and triggers the opening of the ion channels to allow the inflow of particular ions to flow. The flow of ions changes the voltage across the membrane. This change in membrane voltage is a postsynaptic potential and is a type of graded potential.
B cells engulfs bacteria or toxin and then digests it. Then , it represents the antigen on its surface. The b proliferates into memory cells and plasma cells(they act of the foreign substance). Eventually a helper t cell comes on it's way and triggers more cells.
Answer:
Duplication of hox genes is important in the radiation of animals because they are regulating genes of symmetry and the body plan of the animals' bodies. Some change or mutation in these genes during duplication can cause mutations and with these evolution of the species as it controls the different segments of these animals as they develop, launching the genetic programs that form various body structures, such as limbs and organs. .
I would say excretion since that means the process of expelling waste matter.
The correct answers are evolution, genetic mutation and selection.
The early ancestors of horses showed the pressence of digits and now the modern horses have hooves in their limbs. There could be many reasons for the pressence of hooves horses.
These could be due to the genetic mutations, which could have changed the shape of the digits in the limb. Sudden change in DNA can cause mutation and this mutation can change the phenotype of the horse.
There are chances that evolution took place over a period of time that changed the character in the horse.
Natural selection can also be one of the reason for the change in the phenotype of the digits on the limb of the horses.
