The nucleus controls what happens within the cell
Answer: Option B
Explanation: The first line of defense acts a barrier and does not allows the foreign materials to enter inside the body. It includes chemical and physical barriers that are always ready to protect the body from infection.
Example: Skin and mucous membrane.
Skin is largest organ and it acts as a barrier between pathogens and human body. It acts a waterproof material and the pathogens cannot get inside through skin unless the skin is broken.
Mucous membranes also acts as first line of defense and breaks the cell wall of many bacteria entering through the openings of the body.
So, skin and mucous membrane are the first line of defense.
Answers
Hi,are the answers and explanations;
- A flower is responsible for facilitating pollination in a plant.It contains petals that attract insects for pollination.In has the male and female producing gametes for plants thus in facilitating the transfer of pollen grains from anthers to the stigma for pollination to occur
- The pistil and stamen location are position in a manner that pollen grains can be transferred from the anthers to the stigma with help of agents of pollination such as wind and animal.
- Flowers have nectar which is used by bees and other small flying insects in making of honey.The insects enter into the flower when attracted by bright petals. .Both organisms here benefit mutually thus it is called mutualism
- Flowers have bright colors and contain strong odor to attract insects who are agents of pollination.Insects are attracted to visit a flower in search of nectar if the color of the petals are bright and have a good scent.Dull colored petals attract less or no insect thus face difficulty in pollination process because insects as agents of pollination will not facilitate the process in dull colored petals.
- The ovary becomes the fruit while the ovules become the seeds.In a flower, the ovary that houses the ovules will develop into the fruit of the plant.In the ovary, there are ovules which will develop into seeds of the fruit for the plant.
- Pollen grains acts as the male sex cells in the flower that are transferred to the stigma to meet the female sex cells.The pollen grains are produced by the anthers and could be deposited on the female sex cells by agents of pollination such as wind, insects or animals.
- Fertilization takes place in the ovary of the female flower. The pollen grains from the anthers are transferred to the stigma of the female parts by agents of pollination such as insects.At the stigma tip, a pollen tube develops and grows down. The male sex cells then travel down the style into the ovary where fertilization takes place.
- Fruits carry the seeds of a flowering plant.A fruit is a fleshy r dry tissue that surround the seeds of a flowering plant and could be edible.Fruits harden to make seed access difficult thus protecting the seeds.Fruits facilitate dispersion process when transferred from place to place by water or animals.
- Male part of a plant flower is called stamen.The stamen is made up of the anthers and filament of the flower.The stamen is responsible for the production of male sex cells.The filament holds the anthers into position to facilitate pollination where as the anthers contains the pollen grains which are the male sex cells.
- The Pistil is the female part of the plant flower.It is composed of the stigma, style, ovary and ovules.The stigma is a landing stage for the pollen grains from the anthers.The style holds the stigma into position to receive the male gametes.The ovary carry the seeds/ ovules and develops into the fruit of the plant.The ovules develop into the seeds of the plant.
- A flower pollinated by insects will have more pollen grains.The insects rubs its body as it sucks nectar in the flower carrying most of the pollen grains on its body.When on the stigma, the pollen are deposited there in sure amounts.However, in wind pollination, most grains are dispersed by wind without reaching the stigma.
- It is better for a plant flower to have another flower pollen grains fertize it. This is cross pollination and it comes with advantages such as development of a new breed of plants, it facilitates development of high resistant plants and can results to plants that have favorable and improved traits as compared to original species.
- Carbon-dioxide gas enters the leaf through the stomata where as water vapor leaves the leaf. Stomata are tiny pores that allow for gases exchange in the leaf.
- Stomata are important to plants because they facilitate the exchange of gases in the leaf.The plant takes in carbon-dioxide through the leaf and release oxygen to the atmosphere.In addition, stomata aid in transpiration process, where plant loose excess water in their tissues to the environment.
- Most plants have their stomata opened during the day than at night to facilitate intake of carbondioxide which is essential for the process of photosynthesis.During the day, sunlight is present thus with enough carbondioxide intake , plants a can make enough sugars for use.
- The stomata can be closed during the day in cases where the temperatures are too high causing excessive loss of water from the plant through the leaves. Such a situation could result to plant wilting thus the plant mechanism could close the stomata to maintain the stored water and avoid wilting.
- Meristematic cells trigger the growth of new cells in the young seedlings at the tip of roots and shoots and forming buds.These group of cells have the ability of division and re-division.
Answer:
None of these two
Explanation:
An unsaturated fatty acid must contain a double bond in the poly carbon chain other than the double bond in the functional group. In these two, images there exists a double bond in the carboxylic group i.e –COOH.
Since none of them have double bond in long poly carbon chain, therefore these two fatty acids cannot be considered as unsaturated fatty acid.
Answer:
To maintain homeostasis
Explanation:
Effectors are organs, cells or tissues that provides the required output after receiving a feedback from the control center. Nerve impulse instructs the effector to bring things into balance and required range. They then influence the magnitude of stimulus and maintain homeostasis.
