which of the following agricultural practices can lead to algal blooms? select the two correct answers.
- sediments released by tilling of soil
- withdrawls of water for crop irrigation
- animal waste accumulated in livestock production
- application of nutrients to crops
- erosion caused by livestock overgrazing

Application of nutrients to crops

withdrawls of water for crop irrigation

Explanation:

Algal bloom can occur when excess of nutrients,hot water temperature leads to excessive growth of naturally occurring algae into thick mats on the water surface. Algal bloom occurs when excess nutrient supply to the crops,warmer temperature and low water supply results in rapid growth of algal bloom.Algal blooms are harmful to aquatic life by obstructing the fin of a fish, reduce oxygen content in water,it can discolor the water,form huge smiley piles on beaches change the taste of drinking water.

desert perennials often survive by remaining dormant during dry periods of the year, then springing to life when water becomes available. most annual desert plants germinate only after heavy seasonal rain, then complete their reproductive cycle very quickly.

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.