According to N.C.F. 2005 in the upper primary stage science curriculum, which of the following is recommended in context to teaching-learning science?

a. In the constructivist perspective, science learning objectives must be contextual in nature.

b. Teaching-learning science can be organized around certain broad and integrated key concepts.

c. Learner's experience has an important place in the process of knowledge construction of Science.

d. During the teaching-learning of science teachers may frequently ask students to ‘think-pair-share.’