It would be primary since the writer himself is getting the information from a direct source.
Due to its short life cycle this fly can easily multiply if its population is not controlled. <span>The house fly is known to carry more than 100 diseases including tuberculosis and cholera</span>
On my work the answer was D ..
<span>An advantage for the angiosperm approach to the formation of nutritive tissue is in energy conservation.</span> <span>The nutritive tissue is formed via double fertilization in Angiosperms. The advantage of double fertilization is that the plant does not invest energy in seed nutritive tissue until after an egg has been fertilized. This means that endosperm (nutritive tissue) starts to develop and store nutrients after it has been fertilized by a sperm cell.</span> Another advantage is that the endosperm nucleus is very active and <span>divides rapidly, so it forms the nutritive tissue very quickly.</span>
