Cold air usually pushes warm air because cold air has a HIGHER DENSITY
One example of passive transport is diffusion, when molecules move from an area of high concentration (large amount) to an area of low concentration (low amount). Molecules are said to naturally flow down their concentration gradient
Answer:
A pollen tube grows from the pollen grain into the ovary
Explanation:
Water is needed for fertilization in several plant groups because the sperm needs to swim to meet the non-motile eggs of the female organs.
<em>However in angiosperms, the pollen germinates and a structure known as pollen tube which contains the male gametophyte (sperm) grows into the ovary where the ovule is located and the male gametophyte is deposited in the ovule to initiate the fertilization process.</em>
<em>Hence, water is really not necessary for fertilization in the angiosperms.</em>
If the Earth were a disk with its surface perpendicular to the rays of sunlight, each point on it would receive the same amount of radiation. <span> However, the Earth is a sphere and aside from the part closest to the sun, where the rays of sunlight are perpendicular to the ground, its surface tilts with respect to the incoming rays of energy with the regions furthest away. Hope this answers the question.</span>
Answer:
A
Explanation:
From what I know this could be wrong, but in the four stages of natural selection, the first step is overproduction, the second step is adaptation, and the third step is competition or survival of the fittest. This means that only the organisms with the best adaptations for their surroundings will survive. COULD BE WRONG SORRY IF IT IS
