Which two statements are true?
a. a moving magnetic field creates an electric field.
b. a constant magnetic field creates an electric field.
c. a constant electric field creates a magnetic field.
d. a moving electric field creates a magnetic field

Answer : A. A moving magnetic field creates an electric field

D. A moving electric field creates a magnetic field

Explanation :  

A. A moving magnetic field creates an electric field because when we move a magnet toward the coil then the emf induced in the coil that means the current induced in the coil and the induction shows the electric field .

D. A moving electric field creates a magnetic field because when charge moving or electric current passes through a conducting wire then, create the magnetic field around the wire.

Explanation:

Microalgae can offer several benefits for wastewater treatment with their ability to produce large amounts of lipids for biofuel production and the high economic value of harvested biomass for biogas and fertilizer. This study found that salt concentration (∼ 45 g L⁻¹) had more of an effect than salt type on metabolisms of Chlorella vulgaris for wastewater treatment and biofuel production. Salinity stress decreased the algal growth rate in wastewater by 0.003 day⁻¹ per mS cm⁻¹ and slightly reduced nutrient removal rates. However, salinity stress was shown to increase total lipid content from 11.5% to 16.1% while also increasing the saturated portions of fatty acids in C. vulgaris. In addition, salinity increased the algal settling rate from 0.06 to 0.11 m day⁻¹ which could potentially reduce the cost of harvesting for algal biofuel production. Overall, C. vulgaris makes a suitable candidate for high salinity wastewater cultivation and biofuel production.