Mutation are two types somatic and germ cell mutation...as there is mutation in germ cell it will alter the normal behavior and produce variation !
random fertilization also causes variation as different setup of genes meets with another different...so chances of variation increases !
and third crossing over is in meiosis when chiasmata forms....so in this two homologous chromosome attach to each other and on separation ... some part exchange so leads to variation !
Answer:
The changes in the single base or nucleotide in the nucleotide sequence and thus changing its complementary base also it is called as point mutations, while when there are insertions or deletions of more than one base pair in the nucleotide sequence it is known as frameshift mutations.
Natural selection is the process in nature by which organisms better adapted to their environment tend to survive and reproduce more than those less adapted to their environment. For example, treefrogs are sometimes eaten by snakes and birds.
Answer:
Muscle tissue and neural tissue
Explanation:
Excitability refers to the ability of muscle and nerve cells of the respective tissues to respond to a stimulus and generate an action potential. Both muscle cells and neurons respond to a stimulus and convert it into the action potential.
Action potential refers to the electrical signal. Propagation of action potential along the membranes of these cells results in muscle contraction and functioning of neurons.
The membrane potential of these cells changes in response to the stimulus and the changed potential is propagated to the other cells.
<span>Large-scale evolutionary trends are the result of macroevolution.</span>
