Before coming up for air, seals can remain underwater for upwards of
a. 1 hour.
b. 1.5 hours.
c. 2 hours.
d. 2.5 hours.

I just took the quiz and C) 2hrs is wrong

ng

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.

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.