Thymocytes that are not selected during Positive Selection: Group of answer choices are eliminated because of their reactivity with foreign antigens are most of the developing thymocytes and die by apoptosis in the thymic cortex are exported to the periphery, where they are phagocytosed by macrophages undergo genetic reprogramming and differentiate into a different cell type try out different beta-chains to acquire reactivity with self-MHC molecules

the element that provides strength to the exoskeletons of clams and oysters is phosphorus.

this is so because calcium carbonate is the main component in the shells. calcium carbonate is strengthened by phosphorus.

explanation:

the answer is 1. photosynthesis. glad to

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.