Plant cells, unlike animal cells, are characterized by the presence of a a. cell wall and a contractile vacuole b. cell wall and a central vacuole c. nucleus and a cell wall d. nucleus and a contractile vacuole

the correct answer is option b

behavioral response need communication and thus co-ordination at several levels such as interaction among cells, organ system and the entire organism.

behavioral response produces both internal and environmental stimulus.

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.