Which best describes fetal development? The heart beats and is heard during the first trimester.
The heart beats and is heard during the second trimester.
The heart beats during the first trimester, but is heard in the second trimester.
The heart beats during the second trimester, and is heard in the third trimester.

the answer is "a.) well–developed vascular system."

explanation:

correct answer: understand the different control methods available

integrated pest management is an strategy that is based on the ecosystem and try to prevent the pest and the damage caused by them by applying combination of technique like habitat manipulation, biological control and use of resistant varieties.

the main aim of the integrated pest management is not to completely eliminate the pest but to strengthen the ecosystem so that conditions are favorable for plants and unfavorable for pests.