Question

help me to solve this

Answer 1

the answer of 30th qstn is as follows
25 th
a.sodium and chlorine .
b. chlorine
c.hydrogen
d. it prevents from spoilage of food and it is used in fermentation
26.
b.bcz they can easily ract with air moistue etc...

Answer 2

28. ovum has only X chromosome.
but sperm is of 2 types half is of X chromosome and half of Y chromosome
if the zygote formed is of X Y chromosome then the baby born will be a boy,
an if it is XX chromosome the baby will be a girl.