Which of the following can combine in a cell to convert a lower-energy molecule into a higher-energy molecule? ADP + P + energy
ATP + P + energy
ADP + P
ATP + P

The reaction that converts a lower-energy molecule into a higher-energy molecule is ADP + P + energy.

Explanation:

ATP is the molecule that provides energy to the cell. It possesses three phosphate groups, each of which is bound by high-energy bonds and the separation of a phosphate by hydrolysis of ATP is strongly exergonic. The energy released is used by the cell to perform its functions.

In order to form an ATP molecule, ADP is required to bind to a phosphate group, a process that requires energy to establish the P-O-P bond, so the reaction, which is reversible, would be:

                                 ATP + H₂O ⇄ ADP + Pi + ↑energy

This is what allows to convert a lower-energy molecule into a higher-energy molecule and permits an ATP molecule to become the energy exchanger of living organisms.

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:

desert perennials often survive by remaining dormant during dry periods of the year, then springing to life when water becomes available. most annual desert plants germinate only after heavy seasonal rain, then complete their reproductive cycle very quickly.