The graph below indicates the amount of water in the dams in each province shown as a percentage of the capacity of the dams - NSC Life Sciences - Question 2 - 2017 - Paper 1

The province with the greatest decrease in water is the Northern Cape, with a drop from 78.1% in 2016 to 34.9% in February 2017.

Let the amount of water in the dams in North West in 2016 be represented by x. The increase of 33.4% can be represented as:

$x + 0.334x = 78.1$

Simplifying gives:

$1.334x = 78.1$

Then,

$x = \frac{78.1}{1.334} \approx 58.6$

Thus, the amount of water in the dams in North West in 2016 was approximately 58.6%.

1. Research alternative methods: This could involve desalinating seawater or cloud seeding to provide additional water sources.

2. Fix existing infrastructure: Maintaining and fixing water pipes to prevent leaks and reduce water loss in the distribution system.

1. Habitat Destruction: Building dams often leads to the flooding of land, which destroys habitats and displaces wildlife.

2. Altered Ecosystems: The creation of a dam can change the natural flow of rivers, adversely affecting the aquatic ecosystems and the organisms that depend on them.

Food security refers to the state when all people have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs for a healthy and active life.

The phrase 'endemic to North and South America' in the extract implies that the army worm is an alien species in Africa.

1. Maize Imports: The army worm may have arrived through imported maize contaminated with the eggs or larvae.

2. High-altitude Winds: It may have traveled across the Atlantic Ocean aided by wind currents.

The method of control currently used to fight the army worm is chemical control, which involves the use of pesticides.

The army worm could lead to crop failures, resulting in food shortages that would increase the dependence on imports and raise food prices, adversely affecting the economy.

The phase in the diagram above is Telophase II.

1. The chromosomes are separated into distinct groups at opposite poles of the cell.

2. The nuclear membranes are reforming around each set of chromosomes.

The diagrams show cells with: (a) 4 chromosomes in each cell (as they are haploid). (b) 8 chromosomes in the original cell (as it is diploid before meiosis).

1. Crossing Over: Exchange of genetic material between homologous chromosomes during Prophase I.

2. Random Arrangement: Independent assortment of chromosomes during Metaphase I.

Genetic diversity resulting from variations in gametes increases a species' ability to adapt to changing environments, ultimately enhancing survival and evolutionary outcomes.

a) Chorion

b) Umbilical cord.

1. Shock Absorption: The fluid protects the fetus from mechanical shocks.

2. Temperature Regulation: It helps maintain a consistent temperature around the fetus.

The respiratory system takes over the function of oxygen exchange after birth.

If part D (the umbilical cord) is reduced or compromised, the fetus may receive insufficient oxygen and nutrients, leading to physical underdevelopment or other health complications.