Adaptations shaped by natural selection:
a) are magnified and enhanced through genetic drift
b) are unlikely to be present in humans living in industrial societies
c) may be out of date, having been shaped in the past under conditions that differed from those in the present
d) represent perfect solutions to the problems posed by nature
e) are continuously modified so that they are always matched to the environment in which a population lives

e) are continuously modified so that they are always matched to the environment in which a population lives

Explanation:

The role of natural selection is to select individuals best adapted to a given ecological condition, allowing them to survive and leave descendants in a given environment.

Natural selection acts permanently on all populations. Even in stable and constant environments, natural selection acts in a stabilizing manner, is present, eliminating divergent phenotypes.

However, the environment does not represent a constant and stable system, in fact, it is always changing, both over time and throughout space, which determines different interactions between organisms and the environment.

fertilization, pictured in figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. the egg and sperm each contain one set of chromosomes. to ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. in mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. when a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. in placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in figure 24.23b. the fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. the nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.

explanation:

when a reversible reaction is occurring in both directions at the same rate; the products and reactants do not change in concentration. a chemical reaction where the compound is broken into its constituent parts.