The amount of gravity on mars. How much power is needed to slow it down enough for it to land safely. Also what angle to put it into mars orbit so it lands where the engineers know where it is going to land.
Genetic variation allows for a greater chance of a population surviving. For example, if a plant species acquires a disease, without genetic variation the disease would just keep getting passed on to the next identical organism and the population would decline and eventually die. But genetic variation prevents that from happening, because you have so many other species in the ecosystem, and genetic variation is a product of sexual reproduction meaning that the offspring of the diseased plant has a possibility of not inheriting the disease.
Answer and explanation;
-The hydrogen bonding in water is a a result of partial negative charge on the oxygen of one molecule which forms a hydrogen bond with the partial positive charge on the hydrogen of other molecules.
-When molecules of water are close to each other, their positive and negative regions are attracted to the oppositely-charged regions of nearby water molecules. This force of attraction is called a hydrogen bond. Each water molecule is hydrogen bonded to four others.
-This important property of hydrogen bond occurs in polar molecules such as water which contains weak, partial negative charge at one region of a molecule and also a partial positive charge elsewhere in the molecule.
Therefore they are consider matter. Remember anything with a mass is matter.