Questions

Heritable variation is one of the four most important factors that affect whether natural selection can occur. These factors include

1) Heritable variation

2) Descent with modification

3) Struggle for survival, and necessarily if the others are satisfied

4) Survival of the fittest.

Heritable variation allows for possibly beneficial, negative, or even neutral mutations to get filtered during each generation by natural selection--weeding out negative mutations, passing on positive and neutral ones. Without heritable variation, species would quickly fall victim to parasites who take advantage of identical genetic material in a population and evolution would not occur.

Variation is the raw material of evolution.

Because arteries have to have thick walls for use of protection. Its when you get to veins where the walls get thinner. And the use of the heart is to pump blood to all of the cells and organs in the body so it would be to transport blood away from the heart.

i.e. 

Arteries = Away from the Heart 
Veins = Back to the Heart.

Nixon

Macronutrients are located on the Top of a Nutritional Label.

Macronutrients are essential substances that the body needs to survive and develop. There are 3 main Macronutrients:

1. Fats

2. Proteins (and)

3. Carbohydrates.

The nutritional label is an important part of any food package. Since the Macronutrients refer to a list of nutrients that we need daily in a pretty large amount are the most important nutrients to sustain our living, commonly they are written on the top of the Nutrition Labels.

India’s first indigenously designed and developed high thrust cryogenic rocket engine generating a nominal thrust of 19 tonnes was successfully endurance hot tested for a duration of 800 seconds on July 16, 2015 at ISRO Propulsion Complex, Mahendragiri.

The engine will be used for powering the Cryogenic stage (C25), the upper stage of the next generation GSLV Mark-III launch vehicle of ISRO, capable of launching four tonne class satellites.

This cryogenic engine of C25 Stage operates on Gas Generator Cycle using extremely low temperature propellants – Liquid Hydrogen (LH2) at 20 Kelvin (-253 deg C) and Liquid Oxygen (LOX) at 80K (-193 deg C).