Which measure would be MOST effective in increasing the human population's immunity against contagious diseases? A. Getting vaccinated against contagious diseases
B. Treating the first person infected with the contagious disease
C. Isolating the first person infected with the contagious disease
D. Distributing antibiotics in the community to avoid the contagious disease

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.

explanation:

b

explanation:

the food storage products of chrysophytes are oils or the polysaccharide laminarin.   formerly classified as plants, the chrysophytes contain the photosynthetic pigments chlorophyll a and c all but the yellow-green algae also contain the carotenoid pigment fucoxanthin.