In 1831 , Charles Darwin visited the Galapagos Islands . While observing the giant land tortoises that lived on these islands , Darwin noted that the shape of the tortoise shell varied depending on which island the tortoise lived. Tortoises on one island had round shells , for example , whereas tortoises on a neighboring island had more flattened , saddle -shaped shells . Which statement BEST summarizes Darwin's explanation for these differences ?

thrombocytopenia, which is a deficiency in blood platelets, can cause bleeding and bruising in the dermis similar to senile purpura. other possible causes include: exposure to ultraviolet rays and aging skin are common causes of senile purpura. senile purpura may also be a sign of collagen loss in the skin and bones.

ans.

gregor john mendel is known for study of inheritance in pea plants. he used garden pea plant for his study, having alternative traits for various characters. he performed cross-breeding in pea plants to check how characters are transmitted between parents to offspring, such as cross between pure tall and pure dwarf plant. mendel studied the inheritance patterns in pea plants for various generations.

thus, the correct answer includes options and f).