Question

• State whether True or False :
(13) Each period starts with the filling of electrons in a new shell.
(14) The wings of birds and those of insects are homologous organs.
(15) Air is optically denser than water.
(16) Nuclear fusion reactions are the sources of energy in the sun and other stars.
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Answer 1

Answer:

true

false

false

true

Explanation:

in each period number of shells increases.

birds wing -feather, insect wing-chitin so analogous