Nature does = environmental stress or changes
The invading bullfrogs ARE HARMFUL. This is because, they cause decline in the population of the native species.
Decline in the population of the native species will throw the ecosystem into a condition of imbalance which will eventually affect all the living organisms that are living in that ecosystem.
The answer to your question would be B
The pregnant woman should be able to reiterate the meaning of breastfeeding such as it is best for babies, economical, easily digested, reduces risk of allergies,milk does not spoil, good for mothers as well. She should also demonstrates some of the different types of breastfeeding positions like cradle hold, crossover and football hold.