Answer:
As the cell ages the volume of cytoplasm increases, enzymes that synthesize DNA move from the nucleus to the cytoplasm, and there is a gradual build up of lipofuscin. While it is unclear how this directly affects the cell, it is known that once the DNA migrates from the nucleus it is unable to synthesizes enzymes.
Explanation:
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Explanation:
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.
Answer:
The correct answer is - option C. alligators; their tails dig holes that hold water during times of drought, and this water is used as a source for drinking water by many species.
Explanation:
Beavers are keystone species as they help other species to get habitat and also help plants to grow by the holes or dams they make. Kudzu is a keystone species of an ornamental plant which lowers the soil erosion in their abundance.
Red cocaded woodpecker is a keystone species as they create pits in the pine trees that are helpful for other species to live.
Alligators also keystone species but not for digging holes and hold water but the influencing the prey and maintaining the animals in the ecosystem.
The answer is true. Bc the stronger they are the more likely they will survive.
