Which of the following is a blood disorder characterized by crescent-shaped, red blood cells and is caused by a recessive allele that produces an alternate form of hemoglobin?
a. huntington disease
b. sickle cell anemia
c. tay-sachs
d. malaria

the farther away the object is from the central star (the sun) it's gravitainal pull on the object is weaker when it is farther

explanation:

correct answer is a. and d.

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.